Your riding ability...skill...and conditioning wil determine if the miles are too many or not. Stopping along the way for gas and breaks usually allows most riders to make their destination as planned. For longer rides I usually take some Aspirin/Tyelnol with me and use it along the way as it really helps with the aches/pains in longer rides. Be sure to add rain gear so if/when you hit storms you won't get soaked!
About the trunk/packing...look at what the load limit is on your 500 and pack accordingly. Anything that can be used as a backrest will help on longer rides and help with the comfort factor.
Good luck and have fun on your trip! Don't forget the camera!
