The oven runs on propane, so if you are in a place without hookups, you can still cook. The microwave/convection oven requires a shore power hookup, or at least a good hefty generator all the time you are cooking. So it depends on your expected style of camping. By the way, the microwave-in-lieu-of-oven is a relatively new option, and a few people have experienced the microwave jumping out of its cubbyhole and smashing the shelf. TM probably still has some work to do in that area. You can see one of the discussions here
http://www.trailmanorowners.com/foru...ead.php?t=7032
or find recent threads by using the Search tool.
As for the solar panel, it can be added later, but it is a lot easier to do it now,
provided that you think you will always park your TM in the sun. If you park your TM in the shade (to escape the sun!), then the panel won't charge very much. Some people have portable panels that can be set up in the sun, and run a cord back to the TM - but then there is the risk of theft. So again, it depends on your camping style. People who camp in the high altitudes of the west, where there are few trees, or in some of the midwest (ditto), tend to love their roof-mounted solar panels. People in the tree-covered east and south sometimes aren't as successful.
Bill