Riven is always a good choice.
She can get away from ganks without Ghost, Flash, or even Boots at early level due to her high mobility from her abilities. You can usually escape ganks at level one provided your Q is taken first.
If you start W, you still have some ability to escape relatively unscathed do to the AoE stun range. This allows for Champs who have to catch up using speed (Rammus, Hec) to be stopped in their tracks long enough to either flash, or ghost away. This is also useful against junglers who are balsy enough to dive you as stunning them under your turret can do a great deal of damage.
Riven's timed use of, Q, E can create long distance between you and the jungler/enemy. Utilizing W to minimize damage, and stopping enemies in their tracks can increase your ability to escape even further without boots. To further your distance even MORE, a good combo is using 2 Qs to escape, and when they get close, hitting them with your third Q for the knockback, creating more distance. After that, follow up with a W if they're in range to stop them from coming closer for a little bit. And then finish off with E to make your final escape. Alternatively, you can start with E for absorbing any form of harass while you make your getaway.
Riven is also a manaless champ, so if you escape a gank with little or no damage taken, you can jump right back into laning with little repercussions. I don't recommend farming early game with abilities, unless you're under your turret. If you are caught without your abilities up, you're a sitting duck.