You need to wear a full-face gas mask, Tyvek suit, duct-taped at the wrists and ankles with rubber gloves (a scubadiving dry suit works well, with the tanks).
When you are finished, you need to burn all the clothes you had with you.
Make sure you keep your vehicle closed up completely, including all inside air controls in the OFF position and all windows up.
When you are done shooting, write down the model and serial numbers of each gun, carefully box them all up with excessive padding so they won't get scratched or damaged in any way and send them via FedEx to me. I'll take care of your guns for you.
Please DO NOT ship any ammunition. I suppose you can bury all the ammunition you don't use along with all the empty cases (in a place that is safe to bury such items).
In the meantime, your children may become exposed in another way to more lead than you would normally bring home, had you not done all of the above.
Take the above as humor.
To answer your question, and before I receive shipment of your valuable guns, yes, you are being a bit paranoid and NO, I DO NOT WANT YOUR GUNS (you keep them!).
When I shot 600 rounds of 357 Magnum lead Semiwadcutters - maximum loads - in a poorly-ventilated area and at the end of the session, my hands and my gun felt slippery and everything was gray, then I knew I had to do some "cleaning up" after shooting indoors in a poorly-ventilated area.
I convinced my doctor to take blood to test for lead and it was elevated (it was not from a one-time occurrence, but was an average of 600 rounds a night for several weeks)! That was the end of shooting all-lead bullets indoors without ventilation. Even then, with all that exposure, the levels were surprisingly not real high (the number seems to have been around 14)!
I just found out what the 14 lead level number meant:
http://health.nytimes.com/health/guides/test/lead-levels-blood/overview.html:
Normal Results
Adults: Less than 20 micrograms/dL of lead in the blood
Children: Less than 10 micrograms/dL of lead in the blood
Note: dL = deciliter
What Abnormal Results Mean
Adults exposed to lead should have blood lead levels below 40 micrograms/dL. Treatment is recommended if the level exceeds 80 micrograms/dL. (Mine was 14)
In children, greater than 10 micrograms/dL of lead in the blood is abnormal. The source of lead must be identified and removed. Greater than 25 micrograms/dL of lead in a child's blood may indicate the need for treatment.
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Since you will be outdoors, you should be just fine. Just wash your hands often if eating. Personally, I don't think you need to throw away your clothes, just wash them separately from the family's clothes.
More than anything, don't worry to the point where you take the fun out of it, but just be a bit cautious.
ENJOY!
Heck, having a Big Mac may be worse for you than any lead you may ingest (if you're CAREFUL)!