Front tires in 2wd are perfectly fine to flat tow. So no need for a dolly there. If you can lock the steering wheel and put the rear tires on the dolly - that's probably okay if it tows straight. In 2wd the front drive system is essentially freewheeling and flat towing should be perfectly fine - for the front drive line (but not the rear).

This is a summary from Marlin with some clarifying edits so not a direct quote, but mostly plagiarized. It explains why you should not flat tow a 4Runner with the rear tires on the ground.

The problem with a chain drive transfer case like the VF2A is that if you tow with the rear wheels on the ground and transfer case in neutral the transfer case output shaft will turn and it will not be lubricated. The gear oil lives at the bottom of the transfer case and needs to be moved by some mechanism to the top of the case where the output shaft bearings are. On Toyota the chain driven cases, the input shaft turns the planetary housing which drives the oil pump. You must have the transfer case input shaft spinning to lube the output shaft and rear seal of the t/case.

In short: you need to either put a dolly under the rear tires and pull backwards with the front tires on the ground (no problem there) or you need to disconnect the rear drive shaft. There is no combination of transfer case and transmission shift positions that will lubricate all of the moving shafts while flat towing. It's very likely that there is enough residual oil on the bearings that they would last a reasonable amount of time flat towing without more gear lube being brought up from the lower case. If you could modify the shift linkage to engage 4x4 (engage the chain drive and therfore front output) you could likely rely on the chain to adequately lubricate the rear output shaft and seal. I suspect this is why you can get away with flat towing a MT version of the FJ Cruiser or possibly even a Limited 4Runner where you can't flat tow other models without some risk of rear output bearing and/or seals running dry. I think transfer case in Neutral (I assume it has that position) in a Limited 4Runner would work.

Hope that helps.

Good luck!

From the Grand Cherokee owner's manual for 4wd vehicles with 4lo.

Recreational Towing — Quadra–Trac II/Quadra–Drive II Four-Wheel Drive ModelsThe transfer case must be shifted into NEUTRAL (N) and the transmission must be in PARK (P) for recreational towing. The NEUTRAL selection button is adjacent to the transfer case selector switch. Shifts into and out of transfer case NEUTRAL can take place with the selector switch in any mode position.

CAUTION!DO NOT dolly tow any 4WD vehicle. Towing with only one set of wheels on the ground (front or rear) will cause severe transmission and/or transfer case damage. Tow with all four wheels either ON the ground, or OFF the ground (using a vehicle trailer).

And the Toyota 4Runner manual says...

Dinghy towing
Your vehicle is not designed to be dinghy towed (with 4 wheels on the ground) behind a motor home.

!NOTICE
To avoid serious damage to your vehicle
Do not tow your vehicle with four wheels on the ground.

We're both on the same page. I was just commenting on the somewhat unintuitive part about putting the transmission in Park.

There is no good way of towing a 4R with all the wheels on the ground.