This is the Great Legend Shemp Howard here coming at you live from Armadillo people! Today I am going to let you in on my little secret on How the West Was Won.
The best place I have received XP is Twin Rocks! TWIN ROCKS PEOPLE! In the old days prior to the patches I would get about 1750 XP in under a minute on this hideout.
Currently if you clear this hideout in under a minute you will average about 600 XP. 600 XP a minute is great XP. When you go to Twin Rocks you will want to bring a Evans Repeater (from the Pike's Basin hideout) and/or a Bolt Action Rifle (from the Tumbleweed hideout). The first time you do the Twin Rocks hideout make sure you go inside for the Mauser pistol. It is a great weapon to take out the Walton's Gang from up close.
Before you start make sure you have a full bar of Dead Eye and make sure you have multiplayer aiming set to Casual in the options. For the best score make sure you kill all 22 Walton's Gang members in one kill combo. If you kill them under the one minute mark you will get an average of 600 XP.