Shit shoveling:
Indeed only useful if there's no one around.
Do it for xp, especially at early levels.
You can't see train stations if you're freshly 'born', so you have to walk.
Unless you're near VC and have minimal 3 charisma in which case you can do
Doc Andrew's quest.
You still need caps, but you can get those from shit shoveling and selling stuff like junk, flint, roots, flowers.
Better turn junk into brass knuckles or BB's to double the caps you get for them.
Turn flint into primitive hatchet (4x the caps) to gather wood (make sharpened pole for 2x the caps) or to sell it
If you have 40 FA turn flowers (1 cap) and roots (2 caps) into weak healing powder (40 caps).
If you're near NCR, go to Junktown and the Hub.
If you start around in the Hub, carry boxes at the main entry.
It will give you 200 caps and 50 xp.
You can use 100 caps to open a bank account in the Hub and put the other 100 on it.
As far as the mini quests go, at the early levels 300 xp is better than a tool.
Especially as you can use flint for a primitive tool and wood and junk aren't too hard to get.
You can get a free 10mm pistol, 47 ammo and +15% small guns skill from a guard at the Gunrunners.
Only once and only if you have a minimum of 3 charisma and small guns lower than 50%.
Personally I would always put the game on realtime when you don't want to fight in encounters.
Less chance of people entering, more chance to get out of range of enemies, especially if you click to run the moment the map is loaded.
Quests to start with (if you meet the requirements):
Boneyard:Talk to the guard to get a bonus to the Small Guns skill
A Man's Job
Get a Dean's Electronics Book
Convince Jargo to produce more howitzer shells
Bring items to Monte Carlo
Bring junk for Emma (Miniquest)
Scavenge for Lorraine (New Quest)
Den:Give Nuka-Cola to Metzger
Bring booze for April (Miniquest)
Gecko:Bring a shovel to Dan (Miniquest)
Hub:Investigate for the Sad Wife
Bring a shovel to Dan (Miniquest)
Junktown:Bring radscorpions tails for Mark (Miniquest)
Modoc:Get brahmin hides for Balthas
Grisham's Jerky Delivery
Bring radscorpions tails for Mark (Miniquest)
New Reno:Check Orville Wright's contacts
Necropolis:Deliver Message for Elmer (New Quest)
NCR:Get Buster Cigarettes.
Pay back Mira's debt.
Bring junk for Emma (Miniquest)
Redding:Solve the Jet supply issue for Dangerous Dan McGrew
Convince Doc Johnson to stop selling jet to Redding
Bring a shovel to Dan (Miniquest)
San Francisco:Bring junk for Emma (Miniquest)
Vault City:Investigate for Dr. Andrew
Bring booze for April (Miniquest)
These quests combined with some crafting and encounters can get you to level 4 rather easily.
At that point you should have your main skill over 100.
However you might have to put some xp in the other 2 tagged skills as well and if not tagged perhaps in science (gunpowder, metal parts) and FA (weak healing powder) to get them to 40 if you want to be able to craft those.
Tip:
Have the Man's job quest from the Boneyard and Doc Andrew's quest active at the same time.
It will safe you some caps for the train.
As far as trains go, you can travel cheap if you carry boxes at NCR station and in SF.