Is it safe to build out a van while traveling with a cat?

I have a 2 year old cat and I've been wanting to get on the road and live in a van for about 5 years. I was with my ex who wasn't interested and now I'm not. So I'm going forward with my dream. However, I work music festivals and won't have the time to build out a van completely before having to work the next event. Is it safe to build out a van while kitty lives in it with me?

I plan on getting a car payment for a nice solid van that has low miles and good mechanics. Read on here to invest more in the van than the build since it's your bones and foundation. It is not going to be pre-built since I don't like the options at the places like lazy days. I want something more customized to my needs with my musical instruments and kitty.

With that all being said, is this a super stupid idea and I should just save up to buy someone's van off fb or something? I don't want to risk my kitties health for my dream.