[HummerJim]

I'd have to give my vote to Riverview RV Park, just below Bagnell Dam. I believe they just opened for the season and it's convenient to everything. If you want remote and away from everyone Sherwood Landing is just down W from me and it's open year round. I'd recommend it for a Walden Pond type experience. This time of year I doubt you'd need rexervations anywhere.
The problem with the Grand Glaze Offroad Trail is that this time of year it's very desolate and it's one of those areas of the country where your cell phone won't work everyplace - but the scenery is gorgeous and it's a beginner trail with not a whole lot of big rocks, but lots of big ruts after winter. Lynch has used it for their Hummer experience - be forewarned when it rains you have several narrow but deep creeks to navigate and lots of mud.
I'd highly recommend a visit to Vista Grande, voted the best TeX Mex restaurant in the Midwest for 5 consecutive years and an IMOs pizza too. This is a great time of year to come, before all the bugs are out and the summer people come in for the season - March April and Sept Oct are my favorite months here.