A litte more on the cap...
For Naggy and Vox, if you get on either of the mob's aggro list, there is a level check. If you are level 53 or higher, you will be teleported back to the zone line (as if someone evacc'ed or succored you).
No, for the Sol B part, at level 53 solo you will have some problems getting past the giants that are in the area. If the giants are not up, you can run and hang out on the ledge (near the turn in) and be free of aggro. I doubt anyone trains the giants to this area. The giants are on a 6 or 8 hour spawn cycle, and the turn in guy is on a 24 hour cycle. You could get lucky and show up and there not be any giants but the turn-in guy is up.
My advice would be to start the epic now at level 53. There are many, many steps that you need to collect items. Some of the lower level collections could be done now. Collecting the pearlescent shards would actually net some decent experience at level 53.
Overall, the cleric 1.0 is one of the easiest quests since it doesn't require travelling to Fear, Hate, or Air. The time sinks invloved suck though.