Well, you certainly have a great WIP there! I don't know really how to make a good door, because I bet you've already tried all the simple solutions, though (if you haven't already tried) you could make two doors with hinges running parallel to the ship that open outward, and then put some greebling on top. I think the engines are fine, they just look very powerful! Just a question, what type of SHIP is this going to be? (like military, freighter, scout, etc.) Anyway, what you have there looks WAY better than my WIP SHIP.
<(kidding) Keep up the good work, and I hope to see a finished product (eventually) !