I have done a lot of week long ultra light tours and have had pretty good luck with 700x32 Panaracer T-Serv folding tires which I routinely inflate at 100 psi. I a considering going up to 35-40 mm due to the extra load I will be carrying
I have had good luck with Conti Top Touring II tires. (The "Top" model being the key.) Foldable and come in 28, 32 and 37c. If you are not planning anything rougher than something like the Katy Trail, 32c should be fine. I am not light and don't pack ultra-light and had no trouble with 32c on a cross-PA tour that included the entire GAP trail. Rode the 37c size in MT last year on some very rough, hilly/mountainous roads with no problems.