I don't think the wait times will be 45 minutes, if you are there early. I am saying if you get there 45 minutes before park opening, that gives you a really good chance of having very little wait on your first ride and then maybe not so bad of a wait on your second ride. Like
@mesaboy2 said, it's really hard to say how long the wait is at opening. Plus, they sometimes open the park before the official time, which could put you into longer lines if you just show up at the opening time. I would do TSMM first and then head to RNRC. RNRC has a single rider line that maybe you could do later in the day. The single rider line is shorter than normal standby, but it won't be open immediately after park opening.