I did a front/back usuable winch that fit in the receiver tubes for a smaller vehicle. But not the van.
Some issues: a 12k winch for a van weighs a lot and isn't a picnic to stow. Save some weight and use synthetic line instead of wire; it's very much nicer to work with too. A lighter duty winch might work if you get all the hardware to do pulley winching so as to increase the effective power.
You need the beefier class IV hitch or better, and even then side loads are sketch even if you make a custom carrier plate with the minimal amount of lever to it. Use some thicker wall tubing than many of the generic carrier come with.
Make sure your front carrier tube is up to it; some are pretty flimsy, probably meant for bike racks. On my van it's welded to the frame and bolted, with substantial plate between the two. But I still don't use a carrier mounted winch there.
Using a bumper can work, but again, check your mounting (the bumper and the winch). I ran into a guy with a very beefy bumper...but it had rubber between the eight bolts that attached it to the frame and his winch completely torqued it.
Power; you've gotta run some beefy cable back there. I've used welding cable, but actually got a better deal on a (non rare) 25' length of jumper cabling in pure copper. I use a power pole type connector; there's one in the photo here. You're sucking a LOT of amps so don't scrimp.
I'd recommend using a good fabricator who can make something for you. Doesn't cost much more than buying stuff and doing all that work, especially since some of the aftermarket stuff is made for very much lighter vehicles, and since it's likely you'll have to do some fab work anyway. Drilling thick plate and welding under there is a chore, trust me.
BTW, I sometimes thought the default place for a winch oughta be the rear, since you wanna get outta trouble, not further into it....