How do you recover (mentally and physically) after returning from a conference or work travel? Do you set aside time to catch-up before you even first leave home? What advice do you have to make sure I am bringing all that I learned back?

Ensure to take adequate rest and compile the unique things you've learned. Generate business leads and craft value propositions for your relevant peers. Conferences, business demos, and exhibitions are effective venues for networking and gaining insights into functional nuances.

i find it best to talk about the experience with others whihc often generates more ideas and propoels me forward. 

For me, the most important factor for a successful conference is to have clear goals for my attendance. Clear goals help me select sessions and people / vendors to talk to. It also helps me assess the "success" or value of the conference. If you go with colleagues, schedule time when you all return to pool your observations (I like to have people report on the Top 3 most valuable ideas from the conference) and decide how to proceed with possible initiatives to champion. 

Regarding "recovery" - I usually don't need time to recover unless it is international travel or a red-eye. Then I sleep in!

It depends how intense the business trip has been but do take your time when you are crossing time zones, you need to 'reboot' upon your return. Block your agenda if you arrive during the day so people don't throw in meetings because they know you are returning. Disconnect and make sure your biorhythm is back on track before you go back to the office. When returning from a conference, I do take the time to go through my notes (oh yes, I still do handwritten notes ;-)) and am then highlighting the ones (oh yes with a marker) that I want to follow up on or pass on to my team for them to explore. 

The return flight is always a good time to catch up and distill notes and thoughts from the event into a few key take aways to share. Echoing the comments about staying physically active while on the trip - and as a reset once I land back at home. I do my best to avoid the "double" work days with meetings right after landing at home, whenever possible. 

As far as advice goes - never check luggage, always take up your local contacts on going to dinner (and let them order - be open minded) and take pictures of receipts as you get them to save stress on the expense report.