I've found that an unreliable router is an unreliable router no matter what firmware you put on it because it probably has some kind of hardware defect. Your best bet is to just try another and keep it in such a way that heat is less of a factor. I currently have active two Netgears, a Buffalo (with DD-WRT), and one D-Link. I have retired a Linksys and a D-Link because they were flaky like your one.
As for DD-WRT on the Buffalo router it was much harder than I had expect. Surely an short 8-step process is simple, right? Wrong! I had found out that timing was everything and if you didn't get each step timed right then you were left with a bricked router. It took about an hour or so of trying, but I finally got it to work.
BTW, I'm not that impressed with DD-WRT as everyone else is. The main reason I wanted it was QoS. If the QoS works then it barely works, because I cannot tell. I wanted it mainly to prioritize Skype high (I use it as my home phone), DNS, HTTP relatively high, and file sharing stuff like FTP, BitTorrent, other P2P apps as extremely low. What happens instead? BitTorrent runs rampant, HTTP requests time out constantly, but Skype does seem to work the same. The only thing really gained from DD-WRT was my ability to boost the signal from the router, but it makes the router die faster so is that really a gain?
