You can serve him via certified mail, but that would require that he actually sign for the complaint. If you believe he will intentionally avoid service, your best option is to get him served by the sheriff’s department up there. The best way to do this is to call the office, find out the fees associated and their mailing address, send them a certified check for the cost, with (1) enough copies of the complaint and summons for service and return; (2) return envelopes for them to mail the completed summons both to you and to the courthouse for filing; and (3) your contact information so that they can contact you if they have any problems or service issues. If I know anything else about the party (where he works, who he lives with, etc.) I usually include that in my letter so the sheriff knows where to find him if he is avoiding service at his house.