Increase stealth to about above 100%. Press A before battle starts. Try to move as far from the critters, but press 1(stealth), before ending your turn. If done correctly, enemies will leave you allone and you can walk everywhere without savescumming. Having high perception or "cautious" perk helps being more far away from enemies when battle starts.

What annoyed me in fallout 2 is that stealth or diplomatic characters have problems with highwaymen etc. in this game, contrary to fallout 1 which has tame random encounters in comparison. I hope someone will find this as helpful as I did.