What FG bikes would those be?
Wabi Thunder comes to mind. Kilo WT is a lower cost alternative (Bikes Direct).
In my current situation, I can definitely relate to giving up a road (race) bike for a gravel bike. There are very few good rideable paved roads near my house, but gravel/dirt everywhere. Now, there are some great rec areas near my work (35mi away) where I get my pavement time in. But if I switched to a different job I would have to make a specific drive to get there and I'm not likely to do that when I can just ride a gravel bike from my house and save a significant time driving.
I guess I'd ask what sort of riding do you want to pursue while going walkabout? Are you looking for epic road rides all over the country or backwoods bikepacking adventures? Are you going to do any serious competition during this time?
I'm thinking I'll throw this out there: since you have a van, there is no need for a bike to support long bike-only trips. Besides, vehicles parked in one spot for extended times can be seen as an eyesore by the neighbors or become cantankerous from disuse. I'm also making this recommendation barring any serious competition. 1) gravel bike or light touring bike that will take 38+mm tires, has road-like geometry and some cargo capability. This would be used for most bike transportation as it will easily cover 99% of the roads in the US that a typical car/truck would. 2) a MTB, but it would be a "plus" bike or fat bike. Either 29x3" tires or full 26" fatbike. This will get you most places offroad as well as winter biking if needed. I'd also go with some flavor of dirt drop bar here because I'm a drop bar snob.