The RT program lasts about 2 years including summers(6 semesters).
As for where to study, My advice would be to ask RT's where they went, ask nurses, doctors, etc where the best RT's come from. Ask the programs in you area what their RRT pass rate is and their graduation rate is.
In my area, there is 1 RT school in town, but 3 within a 40 minute drive. The one in town turns out the best RT's with the highest pass rate. One of the major trauma centers here will only hire new grads from this school. The other schools tend to have graduates that don't know their way around the equipment, such as the vents.