So i treated all the rust on the floors and undercarriage with ospho and i must say I'm pretty impressed to see the change.. I have also primed and painted the floors and am ready for insulation. Any tips on flooring or insulation, please feel free to chime in! I appreciate you all!

Hello all!

Im Dan! (a newbie) I just bought a 93 international school bus off a pastor on craigslist for 2700$. Its got 170k miles, new brakes, fluids are clean, transmission allows me to do 65-70mph and she starts right up! She's also got some flashy bells and whistles that include a propane generator, two massive a/c units, and an rv heater. However, I check for rust the day of the sale and noticed some surface rust but didn't think it was a big deal. SURPRISE! I strip the floor down to bare metal and BAM! Rusty floors! I have attached pictures of all my main rust spots. if anyone has any advice, PLEASE HELP. I'm really worried about all the rust. Thanks guys!