I wish I had some good suggestions for you solo-wise, but I don't.  I
basically did LDoN (generally worth 2.5-3 blue of straight XP per mission)
to get through 59.  When I wasn't doing that, I worked over the Katta
guards, especially the ones on the second floor in the big mansion with the
guard sonic wolves outside.  The experience there is safe, but I can't
imagine it's quicker than Velks, for instance.  Generally, you'll have to
kill 4-5 guards for 1%.  Nurga (and Droga) might be worth a crack and on my
server they're deserted.  I've read that mages can solo some of the mobs
near the entrance to PoJ.  If you go to a place like Katta and are
distressed by how slowly your regular xp bar moves, turn it all over to AAXP
and grind out some AA's - I was getting 1% a kill at 59 in Katta.

Same problem here - until I got LDoN. 59-65 went quickly - just need to try
for groups where you are one of the lowest. The easiest way is start a group
yourself and using the LFG tool you can send tells to pick them. It would be
rare to get a 63-65 to group (they would lose too many adv points) but you
should be able to pick up 60-62's.