How hard is it to get a character to the maximum level of everything?

It wouldn't be that difficult, as soon as you get Enchanting to 100 everything else can come along pretty easily. However, it'd be really dull just grinding constantly.

All you need to do is complete 1 large quest, go Elf hunting and it will take no more than 2 minutes to level everything. That's how quick and easy it can be done.

I like leveling up. I like hearing that level-up drum sound once in a while. So lately, I've designed my build to continue leveling up as long as possible. That means using all skills and training skills that are hard to level. The skill that get to 100 last for me is always Lockpicking.

I usually start with magic, and when I get pretty good at magic, I start working on warrior skills. Mostly I just play the game, but in the back of my mind I'm always thinking whether I am leveling efficiently. That means once I level up a skill to 100, I use it a lot less often, and just keep it as back up. When I get good at Light Armor skill, I stop wearing light armor and start wearing Heavy Armor. When I get good at One-Handed, I start using Two-Handed.

This has the side effect of making the game feel more challenging while feeling safe because you know you can always switch to something you are already good at.

I also like leveling up because I get to have more perks, and more health, and more stamina, and more magicka.

Another good thing about leveling up high is you get to see new types of enemies that came with Dawnguard.

What?

Ah, the good old Oghma Infinium cheat.

What this man said. It's that easy.