Sell the house first and make the buyers aware the separate lot is available (maybe at a slight discount). If they do not take you up on the offer, after they purchase you should then sell the lot.
All the best,
I have seen this a number of times in the Colorado Springs real estate market. Most home sellers list the house first with an option to buy the lot. Nothing like getting to deals and advertising once. If the home sells than you can list the lot seperately. Good Luck!