How did you all make decisions about time/money tradeoffs?
One thing we noticed, and many friends have as well, is that it will fill the time allotted to it. This can be another unseen pitfall of the dreaded "Wedding Industry". Everything needs to be booked ages in advanced, that perfect venue isn't available for quite some time, and so the timeline drags on and the longer it drags on the more time you spend on it. For you, it sounds like you've got other life experiences anchoring the date - so just be cognizant that perhaps you should only "start early" on the things that need to be done early and leave a lot of it until later. I know that sounds odd...
The best time/money trade-off is completely eliminating things of course. After that, the more it is a "must do" the more skeptical you should be. For us wedding dress was not a typical puff ball thing but a nice sleek number off E-bay for $60 with about $50 of alterations applied. Looked great, took very little time. Invitations were fairly simple, a guest was a printer and offered them as a gift but we still kept things sane.
Decide on the gift thing. Registries are a pain in the neck for everyone involved, often tempt one into getting all sorts of junk you don't need and make less sense the older you are (you probably already have a functioning household if you are older). We already had two sets of silverware, why the heck would we need another? China? Really? I've never thrown a party requiring such nor have I even attended such a thing. This will waste space in your cabinet and be stuff you have to pack carefully everytime you move. The catch here is registries encourage you to spend your own time to force other people to spend more time as well all to likely acquire things of low utility.
So - there is the "no gifts" option - always a good one. Or for us, we did a Honeymoon registry. We split up into chucks all the expenses associated with our honeymoon (Galapagos) into nice wedding gift sized chunks. We got something of actual utility to us and through descriptions of the trip on the registry site and follow up thank yous afterwards everyone got to participate a bit in our "once-in-a-lifetime" kind of trip. (And we actually invited friends and family to join - in the end there were eight of us on the "Honeymoon" and we were more than half the boat).
For those who had medium/large weddings (80-100 guests), or who have attended them, is it true that you don't remember much and it's super overwhelming? Or did you have a different experience?
I think this comes down to planning and thinking ahead (something you are clearly doing). A lot of "standard" wedding stuff separates you from the guests and turns you into a little puppet show for everyone (a long ceremony, three thousand permutations of family photos at yet another "great photo location" separate from ceremony and reception, speeches, dances, wedding cake shenanigans).
These things, especially for an introvert, are just senseless and trivial interactions with an audience and they take time away from actually talking with your guests. Keep these to a minimum. Our ceremony was at the same place as the reception (a nice garden) and took a bit over five minutes. We attended a friends wedding and they had a lot of nieces that needed things to do in the ceremony, but again everything at the same venue (an aquarium) and theirs might have pushed fifteen minutes tops.
We don't dance and we don't like watching people dance either and DJ's typically just make it hard to talk to people. Plus if you don't make it clear to a DJ ahead of time they will slip into the standard wedding schlep of stupid gimmicky things that again shut down conversions and real human interaction into another checklist of senseless "traditions". So we had a classical guitarist, just one, and it was extremely pleasant.
The one thing we failed at was guest management. There will be people that are genuinely excited for you and want to share the moment. Unfortunately this often means certain guests dominate the interaction. Hence my earlier recommendation to have designated people who provide excuses for you to move on so you can remain polite while not spending half your wedding hearing about a distant relative's cats.
Another interesting option is to break free from the confines of and problems of tables and seating. Friends did this, their venue invited exploration (the aforementioned aquarium) and they actually went with a buffet and mostly standing tables to encourage people moving about and seeing more of each other and the couple. It worked very nicely. Also, buffet cheaper than sit down usually.
So while I was very down on big weddings - it can be done. And since you are thinking about it ahead of time and forewarned I expect you'll be able to put something together that everyone enjoys. That of course has a lot to do with you and your friends and family, so stay true to your intuitions on what you want and ignore the standard wedding advice.
And don't worry *too* much about the price. You can have a wedding, a largish one, in a nice venue by without doing face punch worthy things like a $10K dress.
Oh - and I bad mouthed "location" weddings earlier - it sounds like for you travel might already be an issue for most of your guests in which case this is less of an issue as long as "location" is someplace reasonable to get to (not half way around the world).
I think you are ahead of the game here - you are considering the big picture stuff early in your planning. I'll wager you'll end up with something great in the end.