dude, from what your saying, then run a browser, in chroot via ssh. To your remote X server. You may also want to rub a scrubbing proxy in that environ, (i.e dans guardian or somesuch). While a chroot is not ideal, it is a step up from running just plain ol unprivileged. And it's not like chroots are difficult or anything. As for browser choice. In the end I would just choose one with the least amount of lib deps to keep your chroot clean.
While chroots are not ideal, they do two things which are going to increase your security, 1) they keep the underlying file system out of the way of your real filesystem, so things that might lead to filesystem exploits can't do shit, and 2) keep standard system crap hidden away and minimise the chances of someone on being able to do anything should they be able to exploit a vulnerability in the browser. but to me sounds like your making a non-issue into a mole hill. Even the most limited of hardware can run decent browsers. Why you are insisting on using your access box, when you have another machine is beyond me. Ideally just run a browser on your shit hardware, it's not that big of a deal really, yes mike take ages to load, but meh.... who cares.
