Do you need a Park Hopper p to ride Disney's TTC?

We will be in Florida next week, and since we are staying slightly off-site and I don't drive we are using a combination of the Lynx system and Disney to get around. The Lynx buses are fairly straightforward, but I'm concerned about Disney's TTC. I don't want the Park Hopper p because we are strictly visiting one park per day. The TTC looks like it is located inside of the Magic Kingdom theme park, so does this mean I'm locked into the Magic Kingdom if I don't buy the Park Hopper p?