1) Not a good idea. At least keep it in the shade and roll your windows down to keep the cab reasonably cool if you feel safe with that.
2) Always check your guns monthly or more, and renew the oil. I did the mistake of waiting 2 months on my Omega and had a, thankfully, very small rust spot and no bore rust. Thanks to catching it quickly I was able to rub the rust awaywith oiled patches.My attention must've been on my hawken too much