A slave cylinder is not that expensive but having someone remove and replace the transmission and transfer case is expensive. You should try bleeding the clutch hydraulics first. If that doesn't solve the problem take a look at the master cylinder linkage in the clutch pedal area when you push it in to make sure that is working properly and not damaged. The master cylinder could also be bad and that is a much easier fix than the slave cylinder.
If all that is good and you still have a problem, you should just do a complete clutch job unless the clutch still looks new. I would never just replace the slave cylinder without doing a complete clutch job unless a new salve cylinder failed right after a complete clutch job. If you have someone do it the total cost should range from about $800 to $1400 depending on who does it and the quality of the components installed.
You could have a distorted clutch disc from the overheating along with many other potential problems. I have smoked a clutch before on a car without any damage but I stopped immediately to prevent overheating everything.
2002 FX4 Bright Red Supercab 4.0 SOHC, manual 5-spd & Tcase, 33" BFG MTs, K&N air filter, Modified air box inlet, Gibson SS cat. back exhaust, Bama flash, Hidden Hitch round receiver, Rear helper air springs, Electric trailer brake controller, Line-X bed liner, WAAG bar with KC lights and Wildernest shell.