I am wondering if there is a bp/w setup that I can use in the cold ohio water (drysuit) as well as on vacation (3 mil or less wetsuit). I would like to spend as little money as possible but at the same time I am willing to spend what is necessary to get a durable setup.
I use a SS BP for all single tank diving, whether cold water / drysuit or warm water / 3mm wetsuit. I routinely travel with it, and don't find the extra 4 lbs (above an AL plate) to be a problem. (But, I also don't carry a lot of 'personal' items, and I use a cloth duffle bag, instead of a heavier hard case, for my gear.)
For most single tank diving, a 30lb wing is more than sufficient - you can use a larger wing, but it offers no particular advantage (although it may provide a possibly photogenic U/W 'taco' moment for other divers around you).
As for the 'as little money as possible' comment, you can go to eBay and buy used gear - a used SS BP, a used wing, etc. The savings on the BP will be modest but you can do that. For the harness, you can order online, or buy from your LDS, some 2" webbing, a waist buckle, and some D-rings, and make your own harness. Used wings are usually materially less expensive than new (on eBay, for example) although 1) the number of true single tank wings that show up is a bit limited, and 2) you always run a small risk of getting a poor unit when buying used. Over the years, I have purchased 6 wings on eBay, and only had a problem with one, where a plastic plastic tie-wraps holding the LPI on the corrugated hose failed the first time I used the wing. Other than that I recommend buying used as as an option to at least consider.