should I even bother trying to fix it?

MY daughter jumped into a river with her 8310 in her hand, yes she was excited to go camping. Well, that was 2 weeks ago so there has been plenty of "drying time". I don't know how long it was before she pulled the battery, I have a feeling she didn't pull it very quickly at all. I completely disassembled the phone when I got it but that was about 1 day later and it was already dry inside.

The phone will boot up and if you hold it right you can see the hourglass but the screen doesn't have any backlighting. So I ordered and replaced the screen and it's still the same thing. I get the red LED when I put the battery in and if I hold it just right I can see the hourglass on the screen and even the "verifying security settings" when it boots but that's it. The screen still doesn't have any backlighting so the phone is unusable.

At this point it's been 2 weeks since it got wet and it's been sitting disassembled basically the entire time. Should I just give up and call it lost or is it worth trying to submerge the circuit board in alcohol or something?

It's always worth one more shot but I have a feeling you're sol, that's a long time for a phone to sit with water

With chlorinated water you might have a chance, with river water I see zero chance to save this thing.

I say it's probably dead. :( 83xx phones are SUPER cheap on eBay, though.

It may have been too much time, however there's a technique that could work: with the device still disassembled, wrap the parts in gauze and place them in a bag of rice (I used plain white rice). Make sure the rice completely covers everything evenly, because it's going to pull the moisture out if any is left. I would leave it for a day or two, but that's with things just pulled out of the water; I'll leave you to decide the wait time.
I've done this with 3 of my wife's past LG devices; she's dropped one in the sink while washing dishes, knocked another off the counter into the john, and ran one through the washing machine. The only instance the rice technique didn't work was after the washing machine incident, but I believe a few factors played into a non-recoverable toy - it was a touchscreen (old LG Dare) and 35 minutes of submerging, banging, and spinning. >.<