Frequent crashing can be also caused by using ini presets created by stupid people on the nexus that enable incomplete, unstable and bugged settings that are supposed to be turned off, like they are in the vanilla game. Remove any of those mods which are deemed to 'increase performance' because all they do is increase instability of the game, by having removed objects with scripts that reference them and when the game tries to load an object that does not exist the game will crash very frequently. You should use the new vegas configurator from the nexus, has loads of options like removing specular lighting and other stuff. Bethini does not work that well with new vegas as a ini configuration.