Personally I think a laptop or even a netbook is just not worth the extra weight. I do take a tiny Nokia N-800 internet tablet. It weighs about 7 ounces (it now used the same 2 ounce charger as my phone and camera so no extra weight there) and does WiFi. I updated my journal including uploading pictures with it last year and it worked out very well. It was nice that it takes the same memory cards as my Nikon S550 and that the S550 can create reduced size copies of photos. I was able to find an unlocked WiFi access point in most towns, even small ones.

Actually an email enabled phone is probably adequate for what you want to do.

A lot of folks rely on public library computers, but Tthat has not worked out very well for me. Small town libraries tend to have really reduced hours on limited days of the week. They never seem to be open when I want to use them. Larger town libraries tend to have a wait and a limit of usage time limit that is restrictive.