Welcome to the forum!
1. Your truck should have no problem with this trailer. Our 27DSRL tongue weighs between 900 and 1000 lbs when fully loaded. Total trailer weight about 6800 lbs. Check the towing section of the forum for a lot of great info. Be sure to weigh in at the CAT Scale.
2. We have been totally comfortable in ours to below freezing. We use an oil filled electric heater that looks like a small radiator. It cuts way down on propane use.
Also swap out your current thermostat for a digital Coleman, a direct replacement; about $70.00 at Amazon. This makes a big difference in keeping the interior temperature much more stable. There is info about this on this and other forums. Also be sure to order the Glacial option and 15kw air. We have also put a regular home style faucet in the bathroom sink; about $50.00 at Lowes or Home Depot.
3. There is not a lot of closet space for clothes, just the wardrobes on each side of the bed. There is a lot of space under the bed thou. We have a cap on our truck so can store more clothes in plastic bins in the bed. The bath does have a great amount of storage for towels and personal items.
We love our trailer, a really good choice for a couple. The bath is large and separates the living area from the bedroom. DW can watch TV in the bedroom and I can read in peace and quiet in the living area.
Good luck with your purchase.
2012 Toyota Tundra 5.7 Litre DoubleCab
6 speed, 4.30 Limited Slip, Tow Package
2013 Jayco White Hawk 27DSRL
2010 Jayco JayFlight 26BH sold
Yamaha EF2000is Generators (2)
1996 Honda CB750 Nighthawk