Hi!
This is a nice problem to have, all things put together.
My approach:
1) Only attend bachelorette parties that are smiliar to what you would normally do on a weekend. so, if you are MMM, that means just about none. you don't have to make excuses with detail, just say that you are booked that night (to reading in bed, but only you know that).
2) Showers do not have to be expensive, and are only mandatory for bridesmaids, mothers, old maiden aunts. You can make something as a gift. Give with a set of new tea towels, or "antique" that you found just for them (at the second hand store, of course! like an antique teapot). The shower gifts I received were all at $25 or less and many handmade, and all about setting up a new house. We weren't poor, many had money, and no one thought twice about it, either.
3) I would continue to give cash as wedding presents. $200 is a great, generous amount for good friends, close cousins, etc. Much reduced amounts of course for not so close friends, or those whose destination weddings you choose not to attend. If you are travelling to someone's wedding, too, it is okay to just give $100 as you just spent $100 on the hotel / car trip. For those friends, it is really about seeing you there, you know.
The wedding presents you can budget for, as you can those shower gifts.
Be very Wary of the bachelorette parties! You will suddenly be expected to pay up for unexpected bills.