I'm using 85 on a 1920*1200 res, anything higher looks off.
In terms of direction, its really up to you, you can do the main story line or branch out, there are several "guilds" or factions you can join, each of which has its own main quest chain and various side quests, there's the Companions, the Thieves Guild, the Dark Brotherhood, could join a side and do the Civil War quests, none of these are directly related to the main quest but all have a very set direction and progression.
For finding out if there's anything to do in your current location, just talk to NPCs, that's pretty much it, very often you will overhear things whilst wandering about which assuages some of the difficulty in finding side quests. Always talk to innkeepers as well and ask if they have heard any rumours, nearly always get a few quests of misc objectives from the,.