Modifications and equipment for my T-100

We just purchased a 1988 Trailmanor 26 (3023 equivalent) and will be picking it up in California and driving it to Oregon.

We will be using our 1997 Toyota T-100 to tow it.

I know I need to get an electric brake controller installed with a 7 pin connector.

Toyota has recommended that I get an after market transmission cooler.

The seller says that a weight distributing hitch may not be necessary. From all of the discussion in the forum it seems like weight distributing hitches are pretty much a must. Is that true?

Can anyone recommend a WDH brand? Does anyone have experience towing with a T-100, if so, how do they perform? Also, is the transmission cooler necessary with this trailer?

Thanks Blake in Oregon