[TNBDM]

So I get a call yesterday from my brother-in-law's wife. It seems that her family is having a get together on Monday for the Memorial Day holiday (yes, I'm in the US). Her mother has been trying to hire a photographer to come do a large family portrait as well as some shots of all her grandsons together, but she hasn't been able to find anyone who's willing to do it on Memorial Day.

Enter me, with my nifty DSLR and much-exaggerated photographic skill. I haven't yet learned how to say no, so I agreed to come out Monday morning and do the shoot for the family. I have a whole slew of questions, since this is my first time doing a photo assignment for anyone but myself. Some are technical, some are not. Any and all answers and advice is much appreciated.

First off, they want to pay me. I've told them repeatedly I'm not comfortable taking any money at all until after I've done the shoot and they decide they're pleased with the results. They insist on giving me gas money, which I guess I'm okay with, but as far as payment otherwise, how should I handle that? I'm really at a loss for determining how much my time is worth for doing this. How do you figure out how much to charge someone for a shoot when you've never done a shoot before? And how should you handle doing a shoot for someone like this who's sort of pseudo-family?

Now, the more technical stuff. Here's my gear, so you can keep that in mind:

Canon Digital Rebel XTi / 400D.
Canon 18-55 f/3.5-5.6 non-USM (kit lens).
Canon 50mm f/1.8 (aka the Nifty Fifty, aka the Thrift Fifty).
Tamron 28-75 f/2.8.
Velbon tripod that's older than I am.
Canon electronic shutter release cable.
Assorted filters that fit the kit lens (polarizing, UV, etc.).
I have NO external flash unit as yet (there is a Vivitar 285HV in my future, though).

My understanding is that the family wants to do the main shoot out in the woods in late morning (around 11am would be my guess). The light will be far from ideal, but I'm hoping there'll be enough shade from the trees to keep everybody from looking totally washed out. The secondary, grandsons part of the shoot will be near a creek in the same woods.

Here's what I'm thinking. I'll get there around an hour ahead of time to scope out the area and plan how I want things set up. There are going to be MANY small children involved, so speed is going to be key; knowing how I want it to go before everybody has to get there and stand around waiting for me will make things go much, much more smoothly. I'll set up on the tripod, probably do some mirror lock-up and use the cable release just for that little feeling of extra security it'll give me. Then when it's time to do the grandsons, I'll probably have to resort to handheld and luck (there are about a half dozen of them between the ages of 5 years and 6 months).

What am I not thinking of? What challenges are there going to be in this specific shooting context that I'm not seeing? Any tips for shooting in the woods? For shooting lots of kids? I'll be perusing the tips on this site between now and Monday for sure, but anything any of you have to add would be most helpful.

All I really want is to do a decent job for some nice people. Any advice you can give me to achieve that goal would be most appreciated. Thanks!