Brown Transmission Fluid? Tranny filter? A/C?

Ok, so I'm 17 my mom just got a new car my sister got her new car, my dad has his truck and my grandma doesn't drive. So instead of my mom getting rid of her old vehicle she gave it to me. But here's the thing, she is terrible when it comes to maintaining a vehicle. I'm driving with my hazards on because my Radiator Reservoir sprung a huge leak and it overheats so I have to make very frequent stops and put water in it (I just ordered a new one) I will try to be as specific as possible, this vehicle is a 2001 Ford Escape XLT V6 Engine and it actually managed to go past the 200,000 miles milestone. I checked the transmission fluid today and it's brown. I read that it means that it's burnt and it needs to be changed, obviously, but should I drain it completely and refill? What do I do? What about the tranny filter? Should that be changed too? Also, I live in FL so AC is a must have, but unfortunately it isn't working. The blowers and stuff are working and the car isn't taking the Freon. I was showed how to do it at an auto place so I know I did it right. I think there might be a leak in the pump or something, i don't know. What should I be looking for? I'm no mechanic obviously, I'm just trying to keep this running and I'm looking for a job so I can't afford to have someone else "fix" it for me lol. Please and thank you.

Drop the transmission pan and change the filter and fluid. Don't know about the AC