The Hafit tombs look like something you can take your time over. Jebel Hafit looks good. Al Ain fort and oasis. Jebel Mileiha. Hatta and Hajar mountains. Wadi Wurrayah.
Looks like there is so much more than sand and water
Tell Abraq may be closer to Ajman and looks interesting.
http://www.exploretheemirates.com/#/explore-emirates