Look at the tire sidewall carefully to see if there is any deterioration. Also check the date code ... RV tires are normally good for about 5 years. As for brand, well, Michelins are good, but so are Goodyear, Bridgestone, etc.
Shocks, either Monroe Class C units, which we have, or Bilsteins ... can't go wrong with either. You also might want to consider support/leveling jacks for the back ... we have the 7500# scissor units .... super easy to install and will allow a few inches of frame lift. If sway is still a problem there are several good anti-sway bars on the market.