i also kept my kids with chickenpox in - you may avoid stir-craziness if you have a garden and friends who would like their kids to catch it before school age (my dd's bf was round every day but little so-and-so waited til they were due to fly ome on a family holiday in canada 7 years later to succumb!!)
almost all illnesses are catchable before symptons apprear (am also in favour of vaccn for cp) but that's no reason to take them out and about once they're spotty and shedding viruses like mad. if you congregate with folk you don't know, you increase the risk of nfecting (1) pregnant women - can have horrible consequences (2) other small children - parents not aware (if it's running thro a nursery, they'll know - a stranger in the park - straight roulette)
(3) elderly folk - possibly in unsuspecting other family - if they've already had cp, this can bring on shingles, which can be a devastating disease for the elderly
when desperate - an off-peak train to anywhere, where you can sit away from others and look out of the window
put them ina buggy to a bridge and watch the trains/traffic (ok - we're near the M1 - it helps)
check if any of your friends would like their kids to catch it
remember al those sermons about kids not watching too much tv - forget them - and get yourself onto t'internet to at least make virtual contact
get dh to buy gorgeous, expensive, time-consuming toys - you're worth it
and as to the park - is there a time of day it's practically empty - that's your time!!
good luck!!!!!