Rievaulx Abbey, Yorks.

Rievaulx Abbey ruins
Rievaulx Abbey ruins
English Heritage
The abbey ruins lie in a quiet valley and large parts of the church survive to their original height. There are substantial ruins of other monastery buildings. The site has yielded much archaeological evidence about abbey life, and there is an indoor exhibition. There is an audio tour.
Well worth a visit if you are touring in the area.
In theory, the site is overlooked by the nearby Rievaulx Terrace above, but in practice the view (in 2005) is severly restricted by tree growth.
Rievaulx Abbey from Terrace
Rievaulx Abbey seen from Terrace

York Minster

Or, in plainer English, York Cathedral.
One of the great cathedrals of Europe; a fabulous medaeval Gothic building. Even if you are not particularly interested in architecture or religion, don’t miss this if you are in the area. You’ll be impressed by this soaring creation of intricately carved stone. It shows what our ancestors thought was worth spending effort and money on – while the peasants lived in fetid huts, God and his servants got to use a building like this. And yes it has its own website: York Minster.

Richmond Castle, Yorks.

English Heritage
Richmond Castle stands on a rocky promontory above the River Swale, and overlooking the picturesque old town of Richmond. The castle is Norman, and the towering keep is unusually complete. Visitors can climb up inside it for panoramic views over the castle’s great courtyard, the wide cobbled market place of Richmond, and the land beyond. There is an exhibition space, and a garden, its origins contemporary with the castle, on a terrace overlooking the River Swale. Inside the circuit of walls is a broad spread of green, with the vertical lines of the well-preserved keep soaring above.
The castle is well worth a visit if you are touring in the area. The castle is in the town and there is no dedicated parking. It was here that I encountered the parking-disk system used in North Yorkshire, that involves obtaining a free cardboard disk from a shop (etc), setting your time of arrival, and leaving it on view in your car.
The old town itself is also interesting, as I recall.

Pickering Castle, Yorks.

English Heritage
An interesting castle built on top of a mound surrouded by a deep ditch, obviously a replacement for a Norman wooden + earthwork fortification. Much remains of the outer circuit of walls surrounding the ditch, but not so much of the stone keep. There are views from the top of the mound.
Worth a visit if you are touring in the area.

Ormesby Hall, Yorks.

National Trust
The hall is built of weather-stained stone in a notably plain Palladian style. Originally it was in open countryside but now the suburbs of Middlesborough have encroached on the estate. The two-story service wing on the east was formed out of the earlier Jacobean house. Inside, the interior of the main block, which has some rich plaster decoration and woodwork carving, is a complete contrast to the plain exterior. The service wing contains a fully equipped Victorian laundry. Outside, there is an attractive garden. The fine Georgian stable block is home to the horses of the Cleveland mounted police. A Model Railway group is based at the Hall in the old wing, with three permanent layouts on view.
I found that visiting the Hall was worth a rather tedious drive to reach it.

North Yorks Moors Railway

A preserved steam railway.
The line runs 18 miles from Pickering to Grosmont, with a total of five stations. There is a connecting service onwards to Whitby on the coast, also apparently steam hauled. Network Rail trains serve Whitby and Grosmont too, but the tickets may not be valid on both services. For the enthusiast, the stock book lists about a dozen each of steam and diesel locos, and several dozen coaches and wagons.
The website says that on some dates services are available along the Esk Valley line, which runs from Whitby via Grosmont to Battersby – a 24 mile run, but I couldn’t find any timetable, so if you are interested you should telephone them.
FYI, the Esk Valley line is normally used for the Network Rail Whitby-Middleborough service.
Of the stations, Pickering is a tourist destination, with a castle, Goathland is the film set for “Aidensfield” in a well-known TV series, and Whitby is a port and seaside resort, and folk festival venue. The NYMR base is at Grosmont.
I remember breaking my journey at Goathland for a lengthy walk which stretched my enthusiasm for walking far beyond its limits as I tried to reach some now-forgotten goal. There is a pretty gorge with waterfall near Goathland which is a popular destination for walkers if I remember correctly.
As for the train trip, I was somewhat disappointed to discover that the line lies mostly in wooded valleys with no view of the moors. You can see more of the scenery by driving the A169 from Pickering to Whitby (or at least your passengers will :-).)
This railway is worth a visit whether your interest is fired by tourism or a passion for steam trains.

Mount Grace Priory, Yorks.

English Heritage
In a grassy space are substantial ruins of the small priory church, and of the four-room cells inhabited by the monks. One of the cells has been restored and furnished to show how the monks lived. Each Carthusian monk mostly lived alone in his cell, to which meals were brought. Each cell had its own garden, and its own running water and primitive toilet.
An interesting site, worth a visit if you are in the area.

Knebworth House, Herts.

Knebworth House is famous for the rock concerts held in its park, and, by the more discerning, as the home of Victorian novelist Edward Bulwer Lytton – author of the words “The pen is mightier than the sword”. The house is mainly a Victorian Gothic creation, but a Tudor house was on the site before drastic remodelling in the 19th century. A liberal array of fancy domes and turrets are vividly contrasted with carved bats, griffins and grotesque gargoyles. Charles Dickens and Winston Churchill often visited the house.
Today’s visitor can see the Banqueting Hall, with its varied 17th century influences and craftsmanship, and other rooms of interest. There are two rooms entirely dedicated to the life and works of Sir Edward Bulwer-Lytton, with several personal knick knacks and mementoes highlighting his colourful character. The state drawing room is distinctly Victorian-Gothic, but other areas, including the dining parlour, are typical of the Edwardian re-styling adopted by Lutyens.
Outside there are 25 acres of gardens, including a walled kitchen garden and a dinosaur trail, as well as the park famed for its rock concerts.
Worth a visit, and you can divert yourself for at least half a day as there is plenty to look at. In my ill-spent youth I lived nearby and attended several rock concerts in the park.

Helmsley Castle, Yorks.

English Heritage.
The castle, originally a medaeval fortress, later acquired a luxurious Tudor house within its walls. The castle was rendered unusable at the end of the Civil War. Later still, it was regarded as a Victorian romantic ruin.
Today, the circuit of walls is largely intact. Inside is a wide area of grassy lawn. The visitor enters via a gatehouse and can look at the half of the keep still standing, the other half having been blown up and allowed to fall into the moat. The Tudor residence is now used as an exhibition space. An audio guide is available.
The castle is definitely worth a visit if you are in the area. Other EH properties are nearby.

Hardwick Old Hall, Derbyshire

Old Hall, trees English Heritage
The old hall was remodelled by Elisabeth Shrewsbury before she had the new hall built. The roofless ruins still stand to almost their original height, and visitors can ascend four floors to view surviving decorative plasterwork. Kitchens and service rooms are also visible. The house was partly dismantled in the 1750’s. An audio tour is available, and there is an exhibition in the West Lodge describing Bess’s adventures in architecture.