Ideas

For a young couple the easiest way to gain residency is to have a baby here. Parents and siblings will be given Permanent residency and the child will get automatic citizenship. You can't work until you have a cedula stating that you are 'free to work' ....which could take a year...and you can't apply until you receive the baby's birth certificate.

If you are both US Citizens you will be able to stay as a tourist for up to 90 days, but this is not guaranteed. Note that citizens of some counties are only allowed/given 30 days.

If you apply for residency going the Pensionado route your healthcare premiums will be based a percentage of  your pension

I  get free healthcare in America so  not sure what I want to do on that end either. That will be one of the negatives for moving but I will look more into it. Not really looking to work when I first get there, but my question then would be if I work online for an American company does that count? More than likely I will be using my school basic housing allowance along with my wife for extra income the first 2 years there

Working online is acceptable, as long as you are not targeting CR businesses. If you have a medical condition that requires monitoring, I would advise you not to rely on the socialized medical health care, CAJA,  here. Most expats purchase private insurance which usually will not cover pre-existing conditions, as appointments with CAJA specialists can take a very long time...and there you are 'covered'.

If mobility is a problem, the sidewalks here are terrible ... full of potholes, uneven surfaces and obstacles that you must watch out for at all times. Wheelchairs users usually prefer to use the roads.

Thanks KOHLERIAS,
Good information the walkability is a big factor and kids as well. I will be asking more questions in the very near future about all things costa rica

As far as beach and city, there is not much in the way of good sized towns or cities near the ocean - near being less than 30 minutes.

One option might be San Isidro de El General or Perez Zeledon but it's more like 45 min to an hour from Playa Dominical.

Would suggest you get the Moon Handbook for Costa Rica and start trying to pinpoint an area or two you think might work for you and then go from there with specific questions about those areas.

You can live super well on $2900/month for 2 people, even 3.

Depends on what % CAJA requires for their premium based on that $2900 as he would be required to also pay into a pension as well as healthcare, being under 55. His wife would not be covered for a pension, unless she had her own account.
Raising a family is quite different from being a retired couple.