While I personally am a huge fan of beat mixing, and do it whenever I can, it's not the "end all, be all" of D.J.ing, especially mobile. Clubs are a different story.
My philosophy about music programming and mixing (from a mobile perspective) is: whatever you do, do it deliberately. Once, years ago, I "sat in" with another D.J. who was doing a quiceniera, and I was there to help because he had NO idea what to play, especially for a younger audience. He asked for us to alternate. He played the more standard "Love Shack" stuff, while I was to play the more youth-oriented portions. Cool. When he played, his playing annoyed me in ways I didn't expect. He doesn't beat mix, and that's fine. He had a cd player with fader start, from the mixer, and would slowly crossfade every single transition. Why?? Here's an example of "why not" - The worst transition I remember was when he started playing "Rock With You" by Michael Jackson. That song starts with a fantastic (and easily indentifiable) drum roll. If you slowly crossfade that in, you've thrown away that fantastic intro, which saps the energy right out of playing that song, for me. Worse yet, it makes him seem like he was constantly unsure of himself, trying to "slip" music in, every time, as if to say "is this song ok for you?". You gotta have some confidence!
Even when I'm not beat mixing, I make it a point to keep track of tempos, for the purpose of flow. I agree that going up is generally a better idea, especially at the start of dancing.
My question about following "Love Shack" with "We Are Family" would be: why? No matter what you play when, you should always be able to give a reason (sometimes more than one). If you don't have (at least) one, you need to sharpen (no pun intended) your programming skills.