mmm. for the amount of times I posted on Soundproofing.. I should ask Tom for a Sticky post.
Road noise - Buy Undercarriage tar spray. Jack up acr Remove wheels. Spray into the wheel arch. Will not eliminate the road noise but reduces the resonant noise (Humming) Other option is to buy quiet tires such as Firenza (if on a budget) or Yokohama Advan Db's
Engine noise - Look under the dash. Look for holes in the firewall. Seal the holes with some bitumin type material and soft spongy material. Smae with the floor, roof, rear shelf etc.