The way I see parts, pcb's, etc. going the last couple of years I would guess that you could get $600-$800 for the game and maybe another $200++ for the extra board.
One opinion.
I just about always sell things at the wrong time (it seems).
I am not sure that a lot of collectors would pay market value for the board and would want it thrown in free or for a discount. Might make sense to just sell it separately.
I think the upright was the best version of this game but it's one heavy game and the cabaret is a good alternative. I really wish someone was able to make an enhanced version of the game with new enemies, landscape and goals like capture the flag; etc. Yeah, that's dreaming but you never know...
Oh, and a new version of VR Battlezone for Playstation VR is coming out this fall. Looks cool: