as for getting the bike looked over--if they can, make sure the person who takes it in, specifies that the rider is a big feller, so that they really check and tension the spokes properly. Hopefully the mechanic doing it is good, and that they really listen and do this. As for the rest of looking over the bike, Im sure its in fine shape, but getting the spokes tensioned really really well by an experienced wheel person is the most important thing (and checking the hubs for proper cone adjustment while they are at it).
oh, and on the subject of buying and crying once, thats a good expression, and good racks and really well made panniers are worth it in the long run. Ortlieb and Arkel and both top notch stuff, I got my first set of Ortliebs in 1993 or 4, and they are still alive and kicking and being used by members of my family, which to me was a good example of money well spent-even though at the time they were rather pricey for me. We have newer sets, but overall I find them to be good, solid, waterproof panniers that will last for many years, which given that I use them for commuting a lot, worth it.
Arkels are really well made also, and have a good rep also.
ps, I have toured for a while now, and have always seen the similarity between a heavy loaded touring bike and a 18 wheeler--they both accelerate and brake slowly, both slow down really darn fast on uphills, and we both have to row the gearbox to keep our engines in the right powerband and not lug down.....