There are several interesting sights within easy driving distance of D.C.: Mount Vernon, of course; Woodlawn Plantation; and Gunston Hall.

Yes, Mount Vernon is very interesting. Old Town Alexandria (maybe mentioned above?) would be convenient also for dinner after.

Another vote for Harpers Ferry/Antietam and the C&O Canal. You can also take a quick trip to lose your money at the nearby Charles Town casino. But seriously, that area is very scenic and historic.

For an excellent introduction to the history and beauty of Harpers Ferry, West Virginia, view the "Harpers Ferry Explorer": http://www.harpersferryhistory.org/hfexplorer/index.htm .
It's just 60 miles from Washington, DC, and served by both AMTRAK and MARC (commuter) rail. It also makes for a pretty drive. Shepherdstown is a great destination for dinner and an overnight - just 10 miles up the Potomac River from Harpers Ferry. Enjoy!

Have you mentioned how much you want to spend? There are some beautiful, relaxing hotels and resorts within easy driving distance of Washington, but the best are $$$$ as well as ****.

OK, trip getting closer. As mentioned we have the 1st 4 days set staying in DC of our 7 night visit. We had booked 3 nights in Charlottsville,Va next but have decided against it. We are now looking to stay closer to DC FOR the LAST LEG of our trip. would like to rent a car for these 3 days. Very much leaning to Alexandria/Annapolis area or Harpers Ferry/ Shepherdstown area, one or the other. Not seeing much for Hotel stay/B&B. any suggestions are helpful. Lastly if some locals or frequent visitors can offer opinions on what one will offer vs the other on the 2 areas we are trying to narrow down and complete our stay.

Just one comment - Alexandria is a close-in (and wonderful in its own right) suburb of DC. It is not particularly close to Annapolis, which is about 45 miles northeast (meaning if you want to see Alexandria, do it as part of your 4 days in DC -- Annapolis would be a wholly separate area).

I do think you are really confused about Alexandria and Annapolis, what do you mean? Alexandria is just a couple miles from DC to the SE in Virginia, right on the DC metro line, just a suburb. I think Alexandria is also an entire county, of course (most people mean Old Town when speaking of it as a tourist, you sure wouldn't have any reason to visit the rest of it) just SE of National airport.

I think I already recommended a very nice hotel in Shepherdstown, there are a couple inns/B&Bs (other than the usual chain hotel/motels), not sure why you can't find them. Go to tripadvisor or expedia and see all in the area with reviews, eg http://www.thomasshepherdinn.com
http://www.harpersferryguesthouse.com/

I'm sure there are plenty in Annapolis also

So after 4 days in DC , we will be renting a car and driving to Annapolis , where will be staying for 3 nights and plan on doing things in the area..One day we will drive to St Michael's area . Any suggestions of nice places to visit or dine close to Annapolis ( within an hr or so ) are welcome. We do plan on our return to DC for flight home to make a slight detour and go by and visit Alexandria/OLd Town Alex,since flight is not till the evning. Thks again for everyone's input for our upcoming trip in March.