x/c flop is standard. If you are going to construct a flop CR range, I would prefer the heart in your hand to be with the A not the 7. As played, fold river.

I think you have some incorrect assumptions about what's in villains range so I'll help you out.

Turn: "Decide to second barrel again for same reasons, hopefully can blow him off mediocre holding"

What type of "mediocre" holdings do you think are folding? I think once he calls flop he has 5x, 6x, 4x, or 3x and nothing is really going to be folding. He is also in position so he still has all overpairs in his range. A high that he called your flop CR with might fold, but you should realize that you hold an Ace so you actually block his A high combos that call your flop CR.

River: "Figured a naked Open-ender wouldn't have called biggish bets on flop and turn so a straight was less likely to be in his range. Figured I could rep the Open-ender that just got there as well."

A naked open-ender will definetly call two streets here your turn sizing is not so large that an open-ender would fold, and even if your villain doesn't have odds to call the open ended on the turn doesn't mean he won't! ;P

Hope this helps! Keep up the good work and posting your hands and you'll improve a lot!

-Mush

Thank a lot mush

I think Mush nailed this. I would like to add that every open ender has an overcard as well, so probably figure they have 25% on the turn. 

That's a good point too, thanks Tyler