Increase Brake Performance On '97 Tahoe Questions! I know, Redundant!

[Eman85]

Hi all,
Long time reader and first post.
I have a '97 Tahoe LT 4X4 2 door with rear drums.
I pull a 14 foot trailer with a tractor. Total weight is around 4500 pounds. Pulls pretty good considering. A little lacking in power for the hills on the highway but I just take it easy!
Braking is where it is suffering. I know it is a lot of weight for the truck but I'd like to see what I can do to increase the braking power some.
I considered rear disk conversion but after reading on here it seems it is not a very effective upgrade for the costs.
I have also been reading up on the Hydroboost and other changes.
Front has new disks and good pads, original calipers and hoses. Dealer recently tried to replace the brake fluid but couldn't get the RR to bleed. They did adjust the rears which helped the peddle.
So, if you were wanting to get a little more stopping power what path would you take, aside from buying a 3/4 ton truck!
Thanks for any advice you're willing to offer. I'll try to answer any questions also.

25 year old brake system, what could be wrong? First do you have trailer brakes? If not then that's first. Rear wheel cylinders are a maintenance item they rust and leak. When doing rear brakes it's cheap and easy to replace them and all of the springs. Up grading to a new body style MC will give you a much better pedal, I did it on my 98 K2500 that I tow with.