Turns out getting things set up to ship from Latvia to the States was easier than I had imagined. The trick was getting things taken care of once my shipment got to this side of the big pond.
First my shipment was shipped from Riga to New Jersey. That was the easy part - the people at LASL (Latvian American Shipping Lines) are professional, efficient and helpful -- that goes for both the Riga and US offices taken from New Jersey to Pennsylvania for a random customs check. Then it was held for a week or so there before being shipped to Rochester, at which point the shipment just stayed there. Because the customs officials there "didn't have my phone number". Sorry, the two valid phone numbers LASL gave them for me must have been too much too handle. If you can't handle making choices, just ignore them, right?
Eventually I was given the go-ahead to pick up my shipment, which luckily coincided with the same weekend I had rented a car (which is incidentally WAY easier/less stressful than renting a car in Riga, but only because the States seem to expect less of you). I also thankfully didn't have to pay the $20 storage fee I'd been told I would have to pay. Anyway, I got my shipment in the following condition:
Needless to say, but US Customs seems to exhibit a certain sense of efficiency. Right? Kudos for creativity and complimentary colour use of the red sign next to the green tape. Also, thanks for not stealing any of my stuff. Though to be honest, there were so many books in there I probably wouldn't notice if one was missing.