help me pick an outdoor vacation

I've never been, but I saw this on HGTV in an episode of House Hunters and I think it fits.  How about Gatlinburg, Tennessee?  

My sister owns an town home in Mt. Snow, VT that they use a bunch & also rent out.

It's not crowded in the summer (or very crowded in the winter, either!) OWS at Somerset or Harriman Reservoir, MTB at Mt Snow, lots of trails around for running and MTBing too, and some SERIOUS hills if you want to road bike

It is gorgeous up there.

Outer Banks, NC?

Asheville/Lake Lure NC?

Great Smokey Mtns.  Bike the Blue Ridge Parkway

We did Greenville, SC and Asheville, NC last year. Both were real pretty areas.  For peace quiet, you may want to try Pigeon Forge, under an hour from Gatlinburg and the Smoky Mnts, so there is a bit of stuff to do as well.

I could suggest TONS of great mountain getaway's, but it get's really limited when you also want outdoor swimming.   Usually mountains and OWS don't go together.  Especially at that time of year.

I was just in Estes Colorado over the winter and they have a large lake as well.  Plenty of cabins to rent as well.  I would worry about water temp at that time of year though.

I missed the part of it being driving distance.  I'm punching out.  I got nothing...

Yeah, if you come from a city of larger than 50,000 or so, Gatlinburg is probably not going to be your thing! :^)   

I was going to suggest a houseboat on Dale Hollow Lake, in TN.   It would be right on the edge of your drive radius though. 

With a houseboat, you get to change your scenery every day, and there's definitely open water available. :^) 

The mountain reservoir lakes in Tennessee and North Carolina would be within your driving radius.  We have a cabin on Norris Lake.  It is a solid 10 hour drive from DC.  I have done that drive many times.  The drive down I-81 across the mountains is worth the trip.

At Norris, the water is very clean.  I swim in our cove in the mornings.  There are lots of cabin rentals.  There is some particularly good mountain biking around Norris.  If you want to ride your road  bike, put on the biggest cassette your have. There will be hills.  Not long like Colorado, but quite steep.  If you want to ride your tri bike, I can give you directions to some flatter roads where you can lay out and crank it.  You would be driving maybe 30 minutes to get to flatter roads depending on where you are staying.  Same thing if you run, you have to change your running style to adapt to the constant up and down.  

http://www.norrislake.com/index.php

You can check similar listings for Cherokee, Douglas, Fontana, and Watauga Lakes. These are all decent size lakes and would have some restaurants choices and things to do, but I don't know much about the them.

We used to have a cabin on Smith Mountain Lake near Roanoke which would be even closer to DC.  It is nice but has built up considerably.   The Tennessee lakes have more land in state and national parks around them so they are less crowded.  The last time we were there we didn't even try to waterski. 

I can tell you more about Norris or Smith Mountain if you are interested.  If you come to Norris, I will take you skiing.

TW

Small world.  Come back.  It is just as good as ever.  

Where was the house you visited? Our cabin is in South Ohio or so it seems by the license plates.  The general area is called Big Creek near La Follette.  We may have seen you and not known it.  I have three daughters about your age.

TW

Its not the mountains but I would suggest Cape Cod.  I am from there so I am slightly biased.  LOTS of beaches etc and you can bike there too.  OR you could do something in Vermont at Lake winipassakee Vermont would be a lot chillier than the Cape.  It is the off season in the mountains of VT and NH.  Many of the ski resorts run the ski lifts so you can bring your mountain bike UP the hill then ride down.

Lake Placid, NY.  TONS of outdoor activities plus there is a little event called the Ironman going on in July...   But seriously, there is plenty to do outdoors without being there during Ironman.  MTB, hiking, rafting, kayaking/canoeing, swimming, running, rock climbing...you get the idea, even non-participatory outdoor activities like checking out the Olympic stuff.