I live about 15 miles from Carlisle so have no experience with local
motels/hotels. All the majors (Comfort Inn, Red Roof, Fairfield, Holiday Inn)
have something nearby.
Your best bet for parking is to enter as "Show Vehicle". It doesn't matter
what you drive as long as it's imported you can enter as a show vehicle.
There are areas for every foreign car made. If you bring your MG so much the
better. Show vehicle admission is $5.00US for the whole weekend. This also
gives you the best parking spot possible. There is also a decent British
Style Pub in Carlisle (Market Cross Pub). Many British and Irish Beers on
tap, authentic British menu. It's close to the Fairgrounds.
I'll be there with my '74 B.