Sequencing sections or something?

I am working on a long piece which will end up about 15-20 minutes. It's pretty fluid with lots of time signature changes (which I am not bothering to enter in Sonar, btw). I would like to be able to work on the piece in sections, so that I can decide to add or subtract bars or individual beats. With a long piece like this, doing this in a seamless efficient way in the midst of composing is hard, because adding a single beat in bar 12 means everything up to bar 486 has to slide over. It works, but it's a PITA since I want to do it a lot. The Insert Time/Measures thing is just asking for disaster if I happen to check the wrong boxes or if the wrong stuff happens to be selected at the time I think of inserting. I wish it were easy to simply say "I want to add/subtract a bar of music here", and have Sonar understand that inserting a bar in some tracks but not others is VERY RARELY something I will ever want.
 
Anyway, what I'd really like to do is work on the piece in sections that are all part of the same project, and then string the sections together for playback. So I can add and subtract bars from one section and know that no other section is affected. I could do it on separate tracks, but then playback is confused and I get into Mute/Solo hell. I could simply add a ton of space between each section, but then I can't skip that space during playback.
 
Is there any way to make working on a long piece easier?

I would ask the same.  Time signatures are fundamental to making Sonar work the way you're wanting it to.  They're really not difficult to add.

I'll add my voice for inserting both the time signature changes and markers. I can't imagine how you're working in different time signatures in different sections without those TBH. No wonder you're finding it hard. Add those and the whole thing will suddenly become much, much easier.

In that case I think you're always going to find working in sections hard work, it's the way the program is designed to work.
 
It's a bit like writing a document in a word processor but not using lines. Doable but hard work.....

OK, I looked into this again, and I just don't see enough value in adding time sig changes. Partly because Sonar's UI is poor for editing them. How about a dialog that has big buttons for the obvious time signatures, and a check box for "Change time signature for next measure only"? Putting time and key signature changes in the same dialog and employing bafflingly microscopic buttons and bare bones options shows me they aren't putting a lot of effort into making time/key signature changes easy to do. It's just way more clicks than it needs to be.

Maybe I'd have to see it to understand, but no matter how Sonar were set-up, adding a bar before bar 15, for example, is always going to push out all the other bars.  Even if the piece were built in sections, added bars in the early sections would push out bars in the later sections.
 
Maybe what you are requesting is to have measure (bar) numbers that start over with 1 at the beginning of each section.  I don't know a way to do that and most people who work in orchestras or bands would find that confusing when the director says, "bar 32."