You don't have to do a lot. 2.5" is something of a gateway between retaining much of the stock driveline and steering, and being forced into upgrades. The RK is ok but you'll need to source shocks and bump stops separately. At that lift I prefer the AEV kit, plus their drop brackets for the front control arms.
A 3.6 with 4.10s can handle 35s. A 3.8 just needs to be re-geared, period. If you have the latter go with 5.13s on the auto, 4.88s manual. A Procal or equivalent is a must.
Jeeps: Where my 401(k) went to die!