As usual late in the game posting a reply.
To everyone who posted with picture of their oven and the kind comments, thank you very much
And yes, from the first one built to the later ones, there has been a lot of improvement, progress, learning, ...
Again thank you for the support I have received from many of the members on this forum.
My advice, being from the food industry having spoken with many current and new business owner.
Don't believe the people who tell you that you can buy a $40k trailer oven + truck + dough mixer + refrigeration +++ and pay for it in 2 month, especially if it is going to be a part time thing. As Nico said, start clean. Buy what you can afford to begin with and slowly grow your business as you generate cash flow.
There are many option to make affordable at first. You can use a kitchen by the hour for $15/ hour to get all your prep done. Much cheaper than buying all the equipment up-front. Simple coolers work great at first, rather than buying a prep table that will require a source of power, loading, unloading, ...
Get the mobile oven from someone who cares and stands behind their product. Putting a piece of concrete on the road is a bad idea overall and things happen.
I have met some people who bought a not so great product and helped them repairing their mobile oven as the manufacturer was given them the run around.
Very doable as a part time business. Since most the business will be weekend and evenings, you can make the best of it.
Insurance is crucial, for your business as you sell food and for your equipment. Smaller insurance companies or one with a local office is going to be your best bet. I can help you get in touch with business owners near you to see who they use.
If you want to send me a PM, I would be happy to discuss further with you. It is often good to bounce ideas off someone before getting started.