You will not be able to do both parks in one day, especially without FOTL. Do yourself a huge favor (and your kids / husband will LOVE you) book a room on site- get the cheapest room you can get, any on site hotel, will probably cost you a few bucks more than getting FOTL for the entire family, but it is soooo worth it. Pick a day in the middle of the week, say Wednesday. Leave your hotel at disney (or where ever you are staying) with a small over night bag, check into your universal hotel EARLY that am, you room will not be ready, but you will get your room keys which will give you FOTL access, hit the parks- go back to hotel when your room is ready, clean up - go have dinner at Citywalk, no-one has to drive back so everyone has a great time, then sleep over and check out, hit the parks again- your FOTL is good for both days, and believe me without FOTL you will not be able to see both parks that quickly.
Plus the fact that a one day pass is not a "park hopper" you can only use in one park. Book the room, you will not be sorry.