Hi Chris.
Your tank set-up plan sounds great. I hope to see some pictures!
Regarding my VG, I house one VG in my 55-gallon. His tankmates include 2 figure-8 puffers, a few mollies and a few bumblebee gobies. I've had him for about almost 9 months and I will fill you in on a few of the nicks that I had run into with the VG.
First of all, he's VERY nocturnal. Absolutely much more active when the lights are out. He LOVES his cave. LOVES LOVES his cave. He will hide in there all day and occasionally I will look over and he will be playing around and kicking up a sandstorm!
The biggest problem I had run into was feeding. Due to the fact that I house him with 2 puffers makes feeding all the more difficult. First few days of keeping him, I fed the norm and he's not eating. I tried spot feeding, but he would get startled and run away, leaving the puffers to scream "OOOOH! FOOOOOOOD!" and greedily eat it all. So, he was getting really, really, really skinny. I eventually had to remove him from the tank and house him in my quarantine tank for a few weeks while he fattened up (he's nice and pleasantly plump now!). When he went back into the show tank, it just went right back into a not-eating, puffer gets all cycle again. I was getting really, really frustrated.......and then I decided to try something completely different. Because he's nocturnal, an hour before feeding, I turned the lights off. It almost seemed to "trick" him into thinking it's night time. And he was out and about and if I spot-fed him, he gobbled it all up without the puffers knowing (hehe!).
So, all in all, you might have to try a few different things in feeding the little guy. They're so shy and virtually blind that it seems like there's nothing you can do. I know a few people who feed the VG at night, rather than the rest of the tank. However, if you house them with little piggy puffers, you might run into that situation. If not, he might be more open to accepting food during the day.
I know it's a bit much, but just figured I'd share my story and maybe you can learn a little something from it. =D