I had the exact same one. I didn't adapt it, only put in a bannister at the top of the stairs, added more steps to the ramp, put vinyl on the floors and added waterproof feet. It had its cover on permanently because the wood was so thin. The floors started to bow and after 3 years I replaced it with what I have now.
You could add better bolts, but I don't know if you have space. Maybe put another layer of mesh on if you want but would your water bottles still fit? And be careful with having it high up because it could get blown over or pushed over.
On a similar hutch I had before this, because let's face it no matter what name is on it, a flat packed hutch is a flat packed hutch. They won't have solid walls or be made to last outdoors long term. But on that hutch my husband attached side and rear pieces over all three sides of the hutch, thicker plywood to insulate it. It didn't look attractive, but it did the job.