I fought outside the first town for an hour before entering at all (at level 2, the level 4 opponents I started encountering were a little difficult).
Generally if you start having a lot of trouble, or have to burn through potions, there are other areas and quests better suited to your level. The games doesn't force you down a narrow path; you are free to explore pretty much anywhere you can reach, so you can run into tough opponents at times (periodic saves can take care of that).
Main plot quests can be delayed until you are done exploring and doing side quests. If you are told to do something by Rhode (or a couple other characters later) you can delay as much as you wish, though if you are told not to do something, you should at least save before trying it (you are given warnings before entering a specific location with high level opponents that is meant to be done later, as well before a main plot event half way through the game that will effect most unfinished quests).
I never had the auto-save kick in in the middle of combat.
With several topics in the forum about running out of potions (merchant inventories reset each time you level), when I started playing I tried to conserve potions as much as possible, and ended up with way more than I needed just from random loot and alchemy. After getting the battle tower, about half way through the game, alchemy ingredients are fairly easy to get, and you can create as many potions as you wish.
Level 1 of Evade helps with melee combat.
A bow comes in handy even without investing in any ranger skills, as (in most situations) it allows you to draw opponents to you, and either kill them or soften them up before they can get to you. Even later when you start running into more archers and mages, a bow is helpful (you may do more damage by Rush Attacking to fight melee, but you don't necessarily want to get in the middle of a bunch of opponents).
