Jared.

Online sites tend to be pretty generic with advice. I was in the same boat as you, in that I was a Boy Scout that loved camping and hiking, and picked it back up after a 15+ year hiatus.

Go to Payless and get some comfortable affordable boots. If you have an old pair of work boots or something, they are fine initially. No need to go out and buy $200+ dollar boots if you aren't going to use them. After 50 miles or so of hiking they will be shot and you will have an idea of what you want/need.

Any backpack initially is fine, I have a few friends that went a whole season with a school "bookbag" with no issues. Load it up with a pocketknife, basic first aid kit, and a bunch of water (preferential here, but I'll go through almost a half gallon in 5 miles during the dead of summer). My "daypack" is a $25 piece from REI.

If you have moisture wicking underwear/pants/shirts go for it. Alot of gym/yoga clothing transitions perfectly to the trail. I routinely use a pair of urban cycling pants for hiking. Good wool socks hiking socks are a must have. Spend the big bucks in this area ($12-15 a pair).

Start small. Go to a local county park you are familiar with and put in 3 or 4 miles without too much elevation, see how you feel.

Make sure when you get into bigger state parks you have maps to work off of, not all trails are marked well.

Give yourself enough daylight. Don't start a hike after work and try to squeeze it in.

Get a map, some water, and get out there. You already have some of a knowledge base from your childhood, and you're an athlete, it'll be easy to get started.