Just dry hop in primary and do a good job at racking to the bottling bucket. No need to cold crash or use gelatin in the batch. Move the fermenter to the racking position 12-24 hours before hand, so that it settles back down again. If you actually gave it enough time to finish fermenting, the yeast will have already started to flocculate (or will have as much as they ever will) before then. Depending on the recipe and yeast used, this could be any amount of time from a few days to a few weeks after fermentation is complete. Dry hopping in primary is no issue (as many have found out).
As already mentioned, it's not a good idea to dry hop in the bottling bucket.
As for the trub on the bottom, that can be avoided if you rack properly. Start the siphon about half way in the finished beer, then move it lower as beer flows out. When you get low enough that you get a little of the bottom sediment too, pull back up a bit until it runs clear again.
Personally, I only move my brews to another vessel when they're going to be aging for a good amount of time on something that works best off the yeast. Such as for a few (or several) months with wood (oak, cherry, maple). Otherwise, I let it go until either it's ready, or I'm ready, to move to serving keg. Giving a brew the time it needs to become all it can be appears to be very difficult for a lot of new brewers. Once you get past that, you'll be amazed at what you get into your glass.