Why Walt didn't think of any backup plan with the RV?

I mean, right from the start he agreed to use this old 1986 Fleetwood Bounder, and as far as I've heard, it's not the most reliable car in the world. And even if it was maintained well, it's still a 20+ years old car, and plenty of things can still break unexpectedly.

Even if he agreed to turn this car into a meth lab, he had to think of something in case it unexpectedly broke. I'm not even talking about how they've stuck in the desert.

What if it would suddenly break in the middle of the road? Besides all the curious people passing by and witnessing both Walt and Jesse, what if some curious police officer would offer to help them? He might have noticed something strange.

Imagine if it was suddenly Hank or Marie coming to/ from work.

"Oh hey Walt what are you doing here with this big ass old RV, cooking meth, huh? Don't worry, I'm just fucking with you. Alright buddy, I gotta go, it was nice to see ya, I gotta catch this Heisenberg fella everyone is talking about. Let me know if you notice someone strange cooking meth, bye"