March - Once you've visited the Papago Well Trailhead and walked the old road an obvious next thing to do is hike up to the ridge between Posta Quemada and Shaw Canyons (with great views of the Whetstones) and down into Shaw Canyon.
April - Shaw canyon exits the south edge of the Rincon Mountain Wilderness and flows into Arizona State Trust Land where an old ranch road meets the canyon, access to the Arizona State Trust Land south of the wilderness is complicated by blocks of private land. From the wilderness boundary we hike up canyon - we don't see any cattle but we can see that they have enjoyed the canyon too, thankfully their impact seems relatively light at the moment.
Exploring the canyon eats day surprisingly quickly and after reaching our previous footsteps in Shaw Canyon we turn around in time to make the slow drive out in the last of the day's light.