why not do away with classes altogether and gave a generic class who is able to do it all (like a cleric, or bard).
everyone starts with the same basic stats (point buy) and skill points+int mod and one feat. He can then purchase more skills with money and skip a turn (training time) and feats (two turns).
As for weapons, they can buy it or find it. Different weapons give you a diff number of swings per turn (simple=1 swing, martial= two, exotic=three). +x weapons give you x number of additional swings (don't hand them out like candy). light, med, heavy armor gives you 1,2,3 aAC bonus (respectively)
The big thing would be everyone is able to cast sells- but only from scrolls that are strewn all over the map. Once you pick up a scroll, you can cast it once a turn. The more scrolls you have- the more you can cast a turn (limit 3)- and no requisite caster level.
since this is a simple game- keep the rules simple. You said you did not want to commit to a long campaign- so simple rules and the fun of rolling is all you nees.