You will absolutely need a cpl for Yellowstone's colorful pools.
Last time my brother came with me I had to lend him my $60 linear polarizer to put in front of his p&s after he saw my photos. Then I ended up lending him and his wife my polarized sunglasses every time they really wanted to appreciate the colorful pools. I would bring polarized sunglasses too - it seriously makes a huge difference.
The pools are best photographed when the sun is higher (when other landscape shots are not so good). Geysers can be shot in various light, but morning and evening are usually best. If you really want to see geysers going off you need to be patient (difficult with a family) or know the 'skinny' and have a plan.
Wildlife (except bison) is another excursion in itself. Not my forte, but dawn and dusk are going to be your best bet.
tulsatom wrote in post #16873132
Sorry for all the questions for would a microfiber cloth be suffice to wipe of any spray if any
Yes and actually spray is not actually that big of a concern, just wipe your lens. I have a thought in the back of my mind that actually with camera lenses you don't get the silica crust because of the lens coating. In any case I have been sprayed multiple times and forgotten to wipe my lens and never had a problem. The last time was with the TS-E and I was a little concerned after realizing I'd been shooting for 10+ minutes and looking at my spotted front element, but everything came off with a wipe. You don't need water or lens fluid either. Car windshields OTOH I know can get spotted with silica. There are a few places by Great Fountain your can can get sprayed, if it happens clean your windows with water.