i took Kamikaze... AFAIK you can take one trait if you want... however bloody mess is funny
well a good advice is to find some buddies to play with, you help them as a good Sniper and in return they can help you with getting ammo and stuff.
Leveling up? first scorpions then pigrats, molerats till you are lvl 6-7 and have at least 120 SG (and a gun like Desert eagle, Magnum 44,Hunting Rifle...Shotgun will do too, but you will have to be cautious) then you go and hunt some little deathclaws (250XP each and only 50 HP, 15% resistance, threshold 2) this is really easy you don't even have to use FMJ ammo on them. You can make some XP on crafting (small guns)
Then kill other stuff and craft till you are level 21
money? sell metal parts (trader pays 100)! easy to get easy to sell. (for me it is 900 caps every 20 minutes) and with some traders you don't need high barter to sell stuff for a good price.
make NCR your hometown, set a tent near it. don't belive or trust anyone. runaway if you see somebody. if you don't hunt then travel naked. don't take more than 150 ammo with you when hunting. get some healing powder(not the weak one)