We own there and just stayed in early May - maybe it's because I have 3 kids, but I felt like I was nickle and dimed to death! If you don't buy a $99/$79 activity card everything except the exercise room, pool and hiking trails cost money, and even with the activity card, there's really not a a lot that is free, you're mostly buying a discount. The owner/Gold card discount to the water park is a joke, and the food options on resort are severely lacking. There are no listed places in the information you're given that serve breakfast, but we found out that the grill in the main building has a few breakfast items - it's the only one onsite that serves breakfast though. A lot of things also close much earlier than is reasonable - 5-6pm. When we were there the outdoor pools weren't open yet and the activities were still on the Spring schedule- which meant that some things were only offered certain days of the week. When we got back I pulled up past Activity guides to see if that was usual and I noticed that during the summer many things still close at 5/6, but most activities are offered more often. I was surprised at how much closed at 5pm during the summer, yet the ski slopes are open till 10-11pm in winter!
Go to the Massanutten Resort website -
www.massresort.com and look at the current activity guide. It will give you the prices and days for the activities.
On the upside, the resort is gorgeous, we had a good time, and I'm sure we'll be back to stay and not just use it as a trader, but the constant paying for things was annoying. We had a horrible meal at the grill in the main building, we all got something different and it was all bad and bland - but the buffet in the Water Park was good. Nice variety, fresh (except the cake) and the pasta bar was intriguing - all for a reasonable cost.
We went to Natural Bridge as a day trip. about an hour drive, maybe 90 min. It was hot as hades, but worth it. We got a combo ticket (discounted online, $80 for the 5 of us) that included all the activities at Natural Bridge and the caverns. Bring a sack lunch, the cafe is uninspiring and there's nothing around for a while. Cavern Note - this is not a commercial venture caverns like you would get at Ruby Falls, or Luray, there are no wide well lit paths gently sloping into the belly of the earth that you view at your leisure. This is a minimally excavated, watch your step, must have a guide into the belly of the earth. It fascinated my rock hound and bored my ballerina. There are a couple of slippery patches, but there are hand rails and anyone in reasonable health who can walk on their own can manage the trek.
On the way back we stopped at Foam Henge. This was the most fantastically cheesy roadside attraction - completely free. I loved it, and I was the only one out of the 5 of us.

The family couldn't wait to get back in the van.
Shenandoah National Park is right there, we went hiking there, planned on the Jr. Ranger Program, but our timing didn't work out. We also went hiking at Natural Chimney. Shenandoah has a parking fee, I don't remember one at Natural Chimney.
Massanutten is only 2 hours from DC. Loads of free stuff to do there once you've paid for the Metro and gotten in.
Monticello (Jefferson's plantation) is also an hour and a half to 2 hours away. We went there a couple of years ago in the fall. It was really interesting. You can also go to Jefferson's retreat at Poplar Forest. We haven't been, but when we were at Natural Bridge, we spoke to some older women who were looking for directions and they commented that their friend said it was a great place to visit - this was echoed by the interpreter who was giving them directions.