If this is useful to someone else, great - any comments or feedback are welcome.
After richyl responded at least twice to my posts that I may want to look at my value betting, and after reading the great thread on blind defense that Deco started and several others contributed to (can't recommend it enough), and after reading a hand analysis that switch started recently, I realized that the pf style I've been using the last two months is virtually designed to avoid postflop play. I was 3betting monsters, medium
hands, and speculative hands OOP and IP - in the blinds, I always 3bet my monsters as well as my speculative hands. I rarely allowed Villain to take the lead unless I had the virtual nuts. This style has worked for me over my time at 50NL - simply increase cbet % as high as it can go, double barrel a lot, and avoid tables where players don't play "fit or fold" poker. This resulted in a dependable, but not spectacular, winrate over 40K hands.
I realize now this is going to hurt me as I move up. I'm losing value because Villains are not paying off multiple streets of value, just the pf raise and (maybe) the cbet. Occasionally I win a huge pot because Villains correctly figure out that my cbet % is too high, and they happen to pick a time to play back at me when I have a monster. But it's been rare for me to get to more than 200BB or so on any table.
The last couple of days I've spent a lot of time trying to play postflop IP (well, the "IP" part was added after I royally screwed myself in several pots OOP). I also watched a cool free (old) video on DC on playing 3bet pots.
It's been a little frustrating - one of the side effects of my pf style of play is that I don't get sucked out on that much, and opening up postflop play for me is allowing that to happen more frequently. It's also been rewarding - I've made a ton of mistakes (several of them for stacks), but I've been learning a lot. The variance feels higher, and I'm still not comfortable going with my reads and betting the river hard enough for thin value. But I definitely get the point, and see how this will increase value over the long run.
Just wanted to share this in case anyone else is where I am. I started by playing tourneys rather than RG's (I only started playing cash in January), so I blame that for not grasping the importance of postflop play.
Thanks to everyone here for helping me see the light (it's still at the end of the tunnel, but it's getting brighter)!