2000 Tacoma power

Any one have any ideas how to add more pullingpower to my 2000 taco. 5 speed 2.7 litter. It can tow my 22 foot camper ok but I want to pull it a lil better. I have added leaf springs g helpers they help alot and a throttle spacer. Also put in the ngk iridium spark plugs. I'm thinking of putting in a heavy duty clutch. This was my dads his baby and after he passed away it is mine now it had 3 miles on it when he bought it it now has 135k. Not one problem. I do have a stabilizer and sway control hitch a d six way plug for my camper. Camper is about 3560 pounds loaded. Any suggestions I'd welcome. I love this truck. Yes I could trade it in but I own it no payments and I love it.