Brian Clemens recently posted a chart of Dynamax external sealants:
http://www.forestriverforums.com/for...-168254-2.html
On our Solera, I use two types- Dicor Self Leveling and Dicor no-sag. For what you pictured, I would clean with acetone, then with denatured alcohol, then fill over the old caulk with no-sag.
Brian’s list may recommend a different caulk than what I use.