The Alarm Clock and rush make no sense

So, Doc goes to the oh, so distant future of 2015.

He does HEAVY MODIFICATIONS to the DeLorean.

These include changing the whole way the time machine works, introducing future technology, like 'Mr. Fusion' and then bringing that tech to the past, where it surely can't ever cause any kind of problems to space-time-continuum.

He also takes the time machine to some car workshop, that does a 'hover conversion' by mechanics, who do not wonder at all about the time travel components, or ask any questions about them, or want to remove or enhance or change them or anything. Just Mr. Fusion and hover conversion (although in reality, it should be called 'flying' instead of 'hovering').

Doc, however, does NOT remove or alter the 1950s alarm clock in any way, because it's completely useless, so of course it should stay. What? Why?

Why wouldn't Doc remove the alarm clock even before going to 2015? Is he that nostalgic about it or what? Even if he is, why keep it in the time machine instead of just bringing it home or something?

In any case, doesn't it seem weird to anyone, that Doc is in SUCH A RUSH to get back to the future that he can't let Marty enjoy his 'new timeline' for a full day before taking him to time traveling adventure shenanigans again?

I mean, he's in a rush, not only to go to the future to change things, which is ridiculous, because information changes the future, so all he would have to do is TELL Marty, and Marty would then remember to do things differently in the future..

..but..

..despite being in a rush, as in they HAVE TO HURRY for some reason, instead of enjoying life in 1985 for two weeks first, he had TIME (with a time machine, you always have time, but movies don't seem to want to conform to this reality) to install Mr. Fusion and do the whole 'hover conversion' BEFORE coming to 1985 and rushing Marty and Jennifer into the future.

What kind of sense does any of this make?

He also had time to learn how to use all this future tech, including the fancy sunglasses, adopt completely new and in 1985 out-of-place future fashion (how can he be so careless to bring future fashion to 1985 and possibly change the timeline again?)...

..but now they are suddenly all in a BIG RUSH to go back to the future (no pun intended).

Why?

Why such a rush, when he OBVIOUSLY had a lot of time, which means, there can't be a rush, because they have a TIME MACHINE and can thus arrive at ANY point in time, even years before anything interesting happens! And if they fail, they can go back again.. and again..

So why is the alarm clock still there, and why is Doc in such a rush to take Marty back to the future?

Also, why would he even arrive back to that exact day, when he could arrive at two weeks later and nothing would be changed (too much)? Why arrive at Marty's place, where he could EASILY have killed Marty (instead of bumping into the trashcan, for example, which PROBABLY wasn't his plan!)?

Again, Doc is SUPER careless here... is he TRYING to kill himself and others, as he did before at the parking lot of Twin Pines Mall?

The more I think about this movie, the less sense any of it seems to make. Am I just going crazy, or does this movie almost literally make no sense whatsoever?