Claudio, I regularly take my clubs in the Mog.
Two alternatives.....
1. If only the bag then the top cover is zipped closed. All pockets etc zipped up.
I use straps to hold it to the rack, the type with ratchet style fittings or similar. Wrapped round and tight to prevent all movement. Never had any issues . Make sure your balls are secured!
2. If taking my Powacaddy electric trolley the golf club bag goes into the passenger side and trolley strapped to the rack again using straps. My trolley is in a Powacaddy bag for it. Battery, shoes, change of clothes all fit behind the seats.
I could at a pinch secure both to the rack but never needed to yet.
My home club is only a 5 minute drive so no problems. I have driven long distances loaded up and no issues. The trolley on the rack does limit rear visibility somewhat but nothing worse than a large suitcase.
If two of you are going then there is really only scope to carry both golfbags on the rack, you might squeeze two small foldable trolleys inside with your other gear though. Easier to hire at the club you visit.
If weather gets rainy then perhaps a cover over the rack? I have never used one as the bag and its own top cover are fine.
Get a range of long straps to make sure you secure the clubs well.
Give it a go......being able to drive in the Mog always puts me in a good mood to play and helps cheer me up after a poor round!
Therapy effect!