For me (and this is just me. 30 years old, single, regular business traveler.) I pack the same things going to Disney that I take when I'm going on a trip for work.
Neosporin with pain killer.
2 types of pain killer (Ibuprophen and Aleve for me).
Nondrowey allergy med (store brand Claritin).
Pepto-Bismal
Immodium
Tylenol PM (to help me sleep the first night. I never sleep well the first night in a new bed).
Benadryl (cause I swell up if I get bitten by spiders)
And, if it's winter, some type of throat drop. Mostly in case the allergy med takes some time to kick in.
That's gotten me through everything I've gotten on a trip with no problems.
Standard disclaimers, I've got a killer immune system so allergies and a few things that go with completely swapping my schedule around are about all I ever have to deal with whether I'm at home or traveling.