I agree with Sall78, you can do whatever you feel like you are capable of doing.  I'm an advocate of pushing yourself while knowing your limits.  That's the attitude I took as a child with RA who wanted to be active and I still see it that way as an adult.  That said, during flares, you will obviously want to do more gentle activities and don't do things that really aggravate the joints where you have active disease activity. 

The only things I really suggest not doing is drinking when you are on medications that affect your liver, and smoking can cause a lot of inflammation.  Other than that do what makes you happy while you are learning your limits.  Say you love to go hiking, so you go hiking for 3 hours one day.  The next day you find that you have overused your joints and are in an awful flare.  So next time you may just want to go for an hour hike and see how you feel after that.  Rheumatoid arthritis may slow you down, but it can't take anything away from you.  Keep doing those things that you love.  Staying active is so important for your health and for your joints.  Keep fighting for the things that are important to you!  Good luck and best wishes!