I think if you know what you're doing, gunslinger is not hard at all, and definitely more enjoyable than a standard mage or fighter class. So here is what I did:
I created a female human with "raised by monks" background. I put one of the initial char points on herbology, 2 on marksmanship, 1 on dex t raise it to 10 and the last one on charisma to be able to recruit the half-orc guy. In the beginning I left the fights for my followers. I used the first few char points to unlock fine revolver, and I made huge profits on selling them, since the revolver parts cost 4 and I can sell back a revolver for 100-200. Hand-crafted flintocks sell for nice profits too.
I solved the bridge encounter with the grenades I found in the cave near to the crash site.
For the next few char points, I unlocked molotov cocktail and raised my perception to 12 so I'll be able to learn level3 marksmanship. That's where I'm now.
I bought the bullets schematic in Tarant, and also bought tons of fuel to create 10+ molotovs. I was able to kill the bulk of the undead in a certain cellar beneath a trapdoor with ease. My companions tank very well, and I can kill a zombie within a turn with my trusty fine revolver. Now I'm out of healing agents, so I plan to go into the wilderness for some herbs. I also plan to visit the merchants and see if they have any chartpelter for sale.
As I said, I'm level 8 now and I can easily see myself advancing to lvl12 by solving the side quests available at this point. I think the gunslinger is not too hard (at least, not until this point) and I definitely enjoy it more than I enjoyed my mage.