I'm a heavy set women like 300lbs would there be rides that I could ride with my kids?

Yes there are plenty of rides that you would enjoy...so many that you might forget that you even had to ask this question...

Yes, there are several rides you should be able to enjoy with your kid(s) at Magic Kingdom like It's a Small World, Pirates of the Caribbean, and Jungle Cruise; along with various sit down attractions like Mickey's Philarmagic, The Country Bear Jamboree, The Carousel of Progress, and Monsters Laugh Factory.

Yes ofc