Hrm I leveled up to 30+ once and up to 10 or 15 a couple more times in about 100 hours played, according to Steam. Leveling never felt slow to me after I learned how the interface worked and got comfortable with the game.
Remember to use Fast Travelling as much as possible - it eats up in-game time, but speeds up your play significantly. Actually running overland from town to town takes forever.
I play on the console, and its lead me to mix feelings about fast travel. On one hand, it does save me probably tons of time from simply retreading the same road over again, and stops me from expending resources on low level mobs.
On the other hand, its lead me to spending a shit load of time on the loading screen. As I'll fast travel to the areas threshold, then enter the area I was traveling too, and get hit with another loading screen.
Its annoyed me so greatly that recently I've started to plan travel routes where I'll be getting the most done with the least amount of loading screens.
I'm not sure how bad this is on the PC version. But frankly, I am frustrated by having Areas, sub areas and interiors (and sub interior) being separated by fucking load screens.
Traveling in the wilderness is pretty freaken awesome in FO:NW as it was in FO3, as it felt rather expansive and seamless.
Like, for example, in the Crimson Caravan, the barracks and office space shouldn't be separated by a fucking load screen.
Some areas, I wouldn't mind so much if they have a load screen, for three reasons.
1) Its a one off seldom visited location
2) Medium to Large in dimension
3) [Optional] Requires something unique to the area to work. (Such as special environment affects, or complicated scripting events.)
So, for the Nelson air force base, the Powerplant/Array I would be okay with it being separated by a load screen. As its kinda of a big area, but one off visit area.
However the Hangar, where whats his name that accepts the scrap metal and the older dude where you get the Quest for the bomber, shouldn't be a separate loading screen as it fails qualifier #1.
I think the more horrific offender with the overuse of load screen is Lucky 38. @.@.
You have the Fast Travel to the North Vegas Gate (1), Entering Vegas (2), Entering Lucky 38 (3), and finally entering the player house at four. Fucking horrible. I loath visiting my house, and only do so when ED is max out in weight, and I'm almost out of ammo or water.