I have some issues to complete quite all Quests i find there.
I am unable to sneak for the necklace. Can't beat Decker and i am not even willing to give the Deathclaw a try.
When i am protecting a caravan, i have to reload like 5 times until it works.

Any tips? It's the second place i visit - am i just stupid or should i visit a different place first?

Maybe you should revisit when you are a bit stronger. I haven't played Fallout 1 for years now, but Decker can be quite a handful early in the game. Come on, Decker, Hub, Deatchclaw, Fallout 1 ofc.

Well the Deathclaw is only a level 17 plagued bear, so if you're around that level you should be good. Don't try to kill Decker Cain, he's there to give you information and identify items for you. As far as keeping the caravan alive, leave around March, and either float the wagon, or take the ferry if the water is above 2'. If you try fording it when it's above 2', there's more chance of it killing off the family members.

Yes, I know it's Fallout 1. It's better to post in the game's individual forum rather than general discussion.

I believe if you post through Galaxy it takes you to the General Discussion forum as opposed to the game sub-forum. Most people don't realize that.

Hm, that would be an explaination.

oh sorry...
i pressed on the fallout 1 page on the "forum" button and thought i am in the fallout 1 forum

Maybe you ought to report it as a bug to the Galaxy devs. I'm not sure they are even aware, but such questions crop up in general all the time.

As with all RPGs, if you run across something that's too difficult to defeat, you can either gain a couple of levels somewhere else and come back later, or you are approaching the problem wrong. Maybe you can talk/sneak/steal your way through the difficult encounter.

Especially in the beginning, in Fallout 1 you could run around the world map looking for random encounters. I remember I used to do this when I was looking to scrounge up some items to trade for better weapons/ammo. I'd save the game, click around the map for some time, and if something like 24 hours went by, without finding an satisfying encounter, I'd just load my save and try again. This way you avoid wasting in game time. Considering that there are no time limits in Fallout 1, you could even skip worrying about wasting time, and just load if you end up in a very unfavorable encounter.

Also I remember there being a trick, where you could plant armed explosives on characters, by using stealing and instead putting items in their inventories. You can cheese through a lot of difficult NPC battles that way. I think I saw that in a speedrun.

About the necklace quest, I seem to remember that you don't even have to sneak around! You can run around the map, you just have to avoid getting spotted by the patrolling NPCs.