First off, a couple of threads that I wrote up to answer a few of your questions.
Advice on tire care
Upgrade from 13" to 14" tires (another ton of capacity combined)
2000 Roo M-18 tire/wheel options
When towing your TT, I can't say that you need to max out the tire pressure on your towing vehicle unless you are maxing out the capacity of the vehicle itself. I typically air up my rears to 5 lbs under the max inflation rating, but i have D rated tires. I really should have E rated on there, but I don't tow all of the time and i liked the size of bfg at ko's that i put on the pickup. One way that I can tell if i'm overloaded or under pressured is when I stop after an hour or so of towing. I walk around both the truck and the camper and lay my hand flat over the tread of each tire and feel for heat in the tires. (Learned that from a big rig driver) If they're cool, everything's okay. If they're hot to the touch (and you'll notice the difference) then I need to either move some weight around or add some more air, depending on where I aired them up before I left. I've always maxed out the trailer tires on the popup and they ran cool to the touch all the time, but I found E rated tires for it, so weight and pressure was never a problem. On my hybrid, those 13" wheels were always hot...i'm lucky i didn't blow 4 tires instead of just the 2 on the trip back from buying it in Iowa. Hence why i started the thread about upgrading the size of tire and rim on the camper. By the way, in the next few days, I will have the tires mounted to the rims and then have them mounted on the hybrid and if all goes well, i won't need a lift or anything extra to make them work. Measurement wise, the 14's that I found are barely any bigger then the 13" tires, but have a 1874 lbs weight limit per tire at 65 lbs of pressure and are D load rated vs the 1360 at max pressure for the 13's and C rated. Maybe you'll get lucky and if you decide to, 14's might work for you as well and relieve some of the pressure of having to watch over the 13's so closely. Pics will be coming soon to the 14" upgrade thread.
Oh...one more thing. No matter what you do, I think the idea of having some TPM's on the trailer are a good idea also since glancing at the trailer tires every now and again while on the road is difficult. Tire Pressure Monitors will help you detect problems before they become worse and overall is just a safety must for anyone with a trailer on for long distances.
Where we've been:
2000 Rockwood Roo M-18 Hybrid
2006 Dodge Ram 2500 Auto 5.9 Diesel
Gone but not forgotten -1986 Rockwood 1003 PUP