I took a quick look at Barnstead's town web site, appraisal office and it sounds like they don't provide info via web.
http://www.barnstead.org/townbusines...gofc_text.html
The only reason Vision has info on a town is because they do appraisals for the towns and the towns ask them to publish it via the web.
The towns you are asking about may not use Vision or may not want the info on the web because of cost or privacy issues.
Probably the best way to check is to see if the town has a web site, and then check for the appraiser's office. If the town doesn't have a web presence they probably don't do anything online.