I'll toss my 2 cents in as well on the kegging. I start with a clean keg. I spray the top of it with Star San, pop the lid and toss it in the Star San bucket. I use my racking cane and tubing to transfer some sanitizer into the keg, taking the opportunity to make sure all internal and external surfaces of the cane and tubing as well as my hands get sanitized. I put the lid on the keg and shake the bejesus out of it, invert it and pull the pressure relief till I get sanitizer out of it. I spray my gas connection with star san, hook it up, and gas the keg a little. Some more shaking and then sanitize and hook up a picnic tap and blow the star san out of the keg back into the bucket. I vent the pressure off and remove the lid, tossing it back into the sanitizer. I position the keg, resanitize my hands and put the tube in the keg so that it reaches the bottom making sure not to contaminate anything and rack the beer in. Once I'm done transferring I put the lid on, spray the gas connections with sanitizer again and hit it with gas, usually adjusting up to 30 psi. I vent it by pulling the relief a few times to purge it, run it to 30, shake it a little and then once it stops taking isolate it since I have other kegs I want to put back online, The next day I run it up to 30 again, shake it a little and again isolate it once it stops taking. After a few cycles of this, I adjust to my normal 8-10. If this were my only keg, I'd probably keep it on 30 for a couple of days and then take it to 8-10.
I've not dry hopped in the keg but like the idea. I'm not overly concerned with clarity so have not used gelatin but have noticed over time the beer will clear. The time it takes or even if it will clear may be different if you dry hop it in the keg. I don't have experience at all there.
Guess that was more than 2 cents but I guess you could say when I keg I focus on sanitation and not introducing oxygen.