Thoughts on this setup

Door sticker shows 285/55R20 (Gulf States Trim package) current are 275/55R20
Wanting to go to LT tires for towing.

So here is what I'm thinking
Factory 18" steels with LT275 /65 R18 Most likely Michelin LTX A/T 2s
Tire comaprison shows this would result in a .4-.5 speedometer error. Actual speed lower than displayed

Couple of questions.
Can I simply transfer my TPS sensors to the Steel rims?
Will E range tires result in an excessively rough unloaded ride? I know that's kind of subjective.
Are the lug nuts different between aluminum and steel wheels?

 

E load will ride harder.

I would not sweat the speedo, mine was more accurate after installing 33s vs the stock 32 inch tires. It will not be enough to worry about. Now if you were moving up to 35s, it would be off a few MPH, but your change is negligible.

TPMS and lugs are different between stock toyota aluminum and steel wheels I believe. Your rims are a special package, could be different from both so I cant off much help there.