Hmmm, if you want your character to get from A to B across diverse virgin terrain, whilst carrying an atv, a Mercedes G-wagon / a 1990's civilian Hummer / 80's Bronco and a trailer for the ATV may do the trick.
As I said in other posts, it has to be new because it has to be an anonymous purchase (anything used would require personal inspection and/or might be followed up by the seller).
I looked at the G-Wagon. I just couldn't get excited about a gas buggy with specs only a little better than a pickup. iirc, it's approach angle is less than 40 degrees, and it's so heavy that when it gets stuck (as everything will), it'd be a major pain to pull out (My shortbox pickup once sank up to the axles in muck hidden beneath a thick bed of leaves. I wrapped the winch cable around the base of the only tree within range, and it became something of a guessing game whether the truck would be out before the tree was completely uprooted.)
Here's the thing . . .
He has access to worlds which are exact parallels to our world -- the only difference is that each is at a different date (from a millions of years B.C.E. up to the 17th Century). But the job is boring and has a lot of annoying rules.
Collectors will pay big money for things they're not supposed to have (e.g. a lot of Mona Lisas were stolen from parallel worlds before the authorities here got wise). Downside is that there's a lot of exposure (having to smuggle your tools of the trade into the transportation hub, having to smuggle the item out of the transportation hub, the authorities monitor the finances of everyone who knows how to use the equipment, more than half of the buyers are actually sting operations, etc., etc. etc.), and if they even suspect you're doing it, you don't have the luxury of a trial: they just ship you off into the dim, distant past and forget about you.
My protagonist's solution -- get a few trusted collectors to front him the supplies so he can set up a base of operations on a parallel world (so he isn't seen buying the tools of the trade), moving the supplies there en masse (so he doesn't have to get things past the guards each time he wants to go somewhen), spend a few years acquiring objects the collectors want (coming home often enough to keep his regular job), and then bringing the goods back en masse (a little tricky, but at least it's a one-time thing instead of having to do it for each piece).
The point at which he can enter a world is usually far away from cities (one of the boring parts of his job is walking miles to the nearest village where he's to check on the price/availability of food/goods and listen to the local gossip before walking miles back to the access point). For his operations, he wants to be able to get in and out quickly, and be able to outrun the horses of anyone chasing him, so his supplies include a lot of ATVs.
One of his clients/suppliers decides to include a SUV/off-road vehicle just in case he might ever need to go farther than an ATV's range.
And it does happen -- an extremely rare, extremely valuable fossil is found, and the best option available is a prehistoric world. He can tell roughly where the access point in that world is in relation to the fossil's location and sees he needs to use the truck to go that distance in a reasonable amount of time.
Since the vehicle wasn't selected specifically for this operation, it has to have the best possible capabilities since there's no way to know what it'll be needed to do. I originally thought a RAV4 or Land Cruiser would work, but then I visited a dealership and saw how poor they'd do off-road.