@Richard Wilson congrats on taking the first steps.
House hacking the first is your best bet. 3-4 family definitely a sweet spot. Not that familiar with NJ as I invest slightly north of you in Orange County (and commute to the city!).
Up to 4 family you should be able to get a mortgage with 25-30% down. Key is to find a local bank that mainly does mortgages, you don’t have to guess, the mortgage officer will usually have a good idea once you give them a few generic pieces of information, without doing a full application. If you have very low debt and as a result monthly obligations, your income to debt ratio will almost always look good and should not be a reason why you don’t qualify.
As to numbers... start with monthly mortgage and tax payments. As to other expenses, I always ask for p&l statements- even if I discount the numbers provided and layer on additional reserves, they will generally be a good starting point.