F1501984

I have a 84 F150 SC that I bought new in 84. Has a 351 4bbl and C6 transmission. It has 208k miles on it. I had the engine rebuilt 15k miles ago . All of the front end parts have been replaced and the brakes including new hard parts like drums, rotors, calipers, wheel cylinders, master cylinder, vacuum booster, parking brake, etc... have all been replaced within the last 6k miles, Upholstry and carpet recently updated. I plan to keep it. The transmission has always had regular fluid & filter changes, usually about every 30k miles or sooner, and I've changed the vacuum modulator out a few times. It drives and shifts about like it did when new. It's seen very little light towing and only been driven by myself and my wife and we baby our vehicles. I have never had a band adjustment done on it although I have read where on C6's that should be done. Right now, it's my daily driver again and I am wondering if I might get another 100k out of it before it needs an overhaul, or should I consider having it rebuilt now. In this area, the best price I have gotten for a overhaul is $950 for a complete rebuild including parts and labor, including hard parts, torque converter and with a 3/yrr 100k mile warranty. That price is if I pull the transmission and take it to them. Add $350 if I just drop off the truck.. My son says I should get it done now so I don't get stranded somewhere. I am thinking that it still has another 75 to 100k miles to go before that's necessary. What can I expect at this point ? Has any of you gotten 275k to 300k miles or more out of your C6 before overhauling it ? At this time I put about 5k miles a year on it.