Just got back and I did standby line for SWMT. I went on an early entry day but I was late getting there. The line said 35 minutes. It was worth the wait. It really wasn't that bad. I know you won't have early entry but if you get there at opening and head straight back, I don't think it will be that bad. Plus you have all day for the other rides. Why not wait in line for a ride you are really interested in experiencing while you are fresh and not worn out from the day yet. I know as the day goes on everyone is less eager to wait in a line. First thing and its done. I actually had a FP for later in the day, so I rode it twice. Once standby and once FP. Keep looking for a FP and try entering specific times. For some reason a FP will show up if you pick a time rather than "morning" "afternoon" or "evening". You should check even when you get to the park.
I also waited in line for PP, just to see the interactive standby line. I honestly enjoyed the line as much as the ride. Hard to believe but I did. I have fond memories of riding this with my Dad (who has passed away). It's very dear to my heart and I wish my Dad could wait in that line with me. So, don't be afraid of standing in line. I wouldn't do really long hour long standby's but 30 minutes doesn't seem to keep me from enjoying all the park has to offer. That's just me. Not everyone feels the same.