Bulldog Van

Can they hold a workshop in it?

Yes and No... it depends on the GM, and what you intend to do with the workshop. Technically, there are plenty of modern examples of working van-workshops, without taking into account the technology advances that make most tools much more compact and easy to manage. Most locksmiths, carpenters, tradesmen, etc. have portable workshops in vans... so it is something that can be worked out pretty easilly with a willing GM.

Well the workshop is for weapons and armor, so I'm guessing it wouldn't take up a lot of space...

Ok, according to Arsenal, I can. Whoo.

I couldn't imagine a GM saying no to it, as long as that is all that is in the back of the van.

The way I imagine it is that it's got a fold down table with the necessary tools behind it when it's up and a removable vice that could be placed in on the rack behind the table as well. That way, when it's not in use, it's not taking up too much space. That's how my dad's workshop in the shed was, since the shed was so tiny.

I personally would probably look at it in terms of what exactly you were going to do with it. Repair or basic maintance on common weapons, sure, fits in a van just fine. Assembled a new weapons from scrap or pieces, sure but couldn't store much in the way of pieces in the van itself, so they would generally need to be supplied. Build a completely new rifle, starting with nothing but steel blanks, not so much.

It'd mostly be for maintenance and modification. And yeah, you'd probably have to bring in the mods as well as what's needed to repair the weapon.

Keep in mind to have a workshop actually setup in your van (rather than just carry around the tools themselves) is an actual vehicle modification itself. However it seems to take up surprisingly little space in 2070 compared to 2060 as it only now takes 1 modification slot (2 if you add in a desktop forge, which in turn allows a vehicle workshop to operate as a facility in a limited manner)