You might consider that the back of the table can be quite close to the wall. Rarely will you ever have to get to the back of the table so it's a waste of space to leave a lot of room behind it. I have just enough space to squeeze by sideways behind mine and in three plus years, I have yet to do it. I think I have about 10 inches from the back table rail to the wall. It's pretty tight in the back right where the snakey wire thingy is located. Still, no issues there. I also suggest leaving enough room in front of the loading side (my left) for an 8' sheet. It's tough to lift one over the machine but easy to slide it into it.
Another thing to consider is the placement of the control box and vacuum pump (if you're going to use one). You can put it in several places and on the front, left or right. Once you have your machine you can decide what's the most appropriate place. You'll also need a place for your control computer with a display and keyboard. That takes up a bunch of room. Don't forget a UPS for the computer. Very important.
I think you're going to have some fun but don't let the frustration get you down. After you've broken a few dozen bits you'll be getting the hang of it. I just broke one two days ago from a stupid programming error. Luckily it was a cheap 1/8" bit. I saw it about to happen and just couldn't hit the stop button quick enough. I suggest you get some extra bits now. You're going to need them. Extra collets and collet nuts are useful too.
ShopBot Details:
2013 PRS 96x60x12 (Centroid upgrade)
4hp Spindle
12" indexer
Aspire
Rhino
Fusion 360
Ferrari 360
Prusa MK3S+
Prusa XL multi-tool