I just spent 5hrs cleaning my boat today, my sundeck for some reason even after regular wipe downs gets deep caked in dirt/sweat.
my recommendation to make your boat like new:
INTERIOR:
Vinyl - since you want something you can get local: Dollar General or Dollar Tree get "LA's Totally Awesome" (clear spray bottle yellow liquid red lettering) don't dilute it, just spray it right on. Spray, scrub w/ brush, then wipe w/ paper towel, repeat, depending on how dirty your boat is and caked in dirt (you'll be surprised) i would do this 2-5x until your vinyl looks brand new.
let dry a bit, then get 303 Aerospace Protectant (found at most auto parts stores or marine stores like west marine) just spray and wipe w/ towell or microfiber.
ok done w/ vinyl
Dash/fiberglass under seats - i found this stuff at west marine, they'll probably have it at local marine stores its called "Starbrite Super Spray" it's good for pretty much anything, fiberglass, vinyl, rubber, metal etc. i spray that on and just wipe w/ microfiber towell
Carpet - Vacuum, and either steam clean w/ a small cleaner or you can just buy "Blu-Coral Dri Clean" found at most auto parts stores, spray it all over the floor and scrub w/ a brush and just let dry.
EXTERIOR
now there are a few options:
long way to do it, is wash it w/ regular soap/water, then mix a 70/30 mix of Vinegar and Water in a spray and go along the boat and spray/wipe clean. IF YOU DO THIS make sure you do a full wax after cause the vinegar will strip your wax.
recommended once a year for me: instead of boat/auto wash use toilet bowl cleaner will strip everything so wax right after
other way is instead of using vinegar use the stuff i mentioned above, "starbrite super spray"
then follow it up w/ a nice quick detailer wax or whatever your choice.
pics below is after my 4-6hr cleaning sessions once a year.
2006 w/ almost 400hrs on it, sits in water during the week.