We got engaged a month ago and my parents offered to throw us an engagement party in their backyard in August which we are VERY excited about! My mom, however, who would be doing most of the planning, has been vacationing in Europe for the last two weeks and will not be back until July, leaving me to handle many of the planning details. I agreed to do so cause it meant that I could pick out invitations I liked, food from the restaurant I like, decorate how I like, etc. However, since its not my money, I feel uncomfortable just booking things like tent rentals and caterers without consulting her first, which has been very difficult to do from across the world. The invitations went out on Monday and we expect to start receiving RSVPs as soon as today so I've been trying to get basic quotes on tent rentals, caters, etc. and send any questions I have back to her. Now she's freaking out about how much this is going to cost her and how many people will be coming. The guest list is up to 100 people and that's largely in part because I was told that my parent's friends -- 26 of them -- needed to be invited in addition to our two families and close friends. This is a party being thrown for me (although I am paying for some of it just out of ease with her being out of the country) and I am starting to feel like I am planning the whole thing AND getting crap for it.
I suppose that isn't so much a question but a rant but I do have some insights I would love from those who have thrown engagement parties, since my mom seems unable to provide me with insight:
-I plan on catering by tray not by person, but is there a benchmark for how much per person/per tray should be ordered?
-is it tacky to ask friends/family to help make some desserts to cut down on the cost of buying from an expensive bakery? if we offer to repay their supplies?
-how can I convince my mom we don't need a porta potty in the backyard?!
Thanks for enduring

Re: Engagement Party Woes
Your Questions:
1. Ask your caterer; it's his/her job to know. There are normally a number of pieces for each tray. Depending on what's on the tray, you'll need different numbers. Also, if this is a meal time, you need enough to constitute a full meal.
2. Yes, it's incredibly tacky. You should not have planned a party your parents could not afford; do not make your friends and family free labor because you couldn't plan. Grab some sheetcakes/cookies/whatever from a nice grocery store or Costco.
3. How many bathrooms are going to be available? For 100 people, you want more than one toliet. And if it's her money and her party, let it go. You've already been spending her money. If she wants a porta potty, let her have the porta potty. There are the nicer ones out there that are basically transportable half-baths.
Isn't it pretty bad etiquette to call 100 people 1-2 days after they receive an invitation to tell them "just kidding, we're canceling it"?
I realize sending invitations out so far in advance is a "wedding thing to do" but its also a polite thing to do. We have people flying in from other parts of the country who would probably appreciate a longer amount of time to book their plans. Plus, it will be easier for me to get an accurate head count for food, drinks, etc. the earlier people RSVP.
A huge party wasn't necessary. That's part of my complaint here. We originally wanted to invite about 75 people in the hopes around 50 would show up. My parents decided to invite 26 of their own friends all of whom have indicated they are coming, putting us at 100. My mom invited them for a party she is paying for and is now complaining about how much its going to cost. That's really my only complaint here.
We're only getting a tent because its in the backyard and my mom is worried that it will rain. If we could predict sunshine, then we would absolutely do away with the extravagant/costly tent. But unfortunately we can't fit 100 people in the house in the event of rain or have a rain date, so sadly, tent. I actually mentioned in my post that I haven't spent any money BECAUSE I feel uncomfortable just booking things without her okay -- which she is not giving me. Its not like I have a credit card or check book and I'm just running around purchasing things. The only thing I have bought so far were the invitations and those I paid for out of my own pocket. My complaint here is that I am trying to get my mom's opinion on how much she would like to spend on food, drinks, tent, etc. and when I am giving her quotes she is not telling me "yes" or "no".
What would be very rude would be to go ahead with the party, but dis-invite some guests to keep your numbers down. I know that you are not planning to do this.
I think that you should read the responses you got on this board again. Others will likely share the opinion that your party is too big, too expensive, and your expectations are not realistic.
I honestly have never heard of an engagement party on the scale that you are describing, and I used to live in the Washington, DC community!
2. I hope you take a lesson from this prior to beginning your wedding planning. Don't accept other people's money unless you want them to dictate your wedding. Don't count on money other than your own unless it is in your possession prior to spending it.
Good luck!