It was important for me when I first arrived here to be able to lean on my new friends. My spoken Spanish was almost nonexistent, I had not lived in the developing world before, and took things like running water, electricity, common sense and bureaucratic sanity for granted. I assumed if I made a mistake and purchased the wrong plumbing part I would be able to take it back and exchange it for the correct one, or that the deposit I paid on water bottles would be cheerfully refunded when I returned the bottle...
In the beginning I feel it is most important to be able to access help, information and socialize in a language one understands. It is really hard to talk about technical details, contracts, and processes during the first year or so and pretty much impossible for the first few months unless Spanish comprehension is a strong point. Most people will need a significant amount of information as they adjust to a new way of living. It is easy to become isolated when you can't understand voices on the radio, TV, read signage. Resources like DR1 can be invaluable, but sooner or later you will have to stand in front of someone and ask for something. You need to be understood and you need to understand the response. Access to English is greater in parts of the North Coast.
If the OP is determined to live in the DR full time, they should pack up the stuff at home that they want here, make arrangements to have it stored and then shipped once their residency is finalized and they know where they wish to live. Arrive as light as you can to make moving and traveling from place to place as easy as possible.
I would suggest renting a place in or near Puerto Plata for 3-4 months, then relocating to SD for 3-4 months, then making their final decision. Who knows, maybe neither place is to their liking and Santiago or Las Terenas will appeal to them more. You can't choose where to live based on the opinions of others and how others choose to spend their money. You need to walk that mile in your own shoes. $2500/month for me, would be limiting. I think that with inflation $3000 is the minimum that a first-worlder would need to not feel like they are constantly compromising. Having a little $$$ left over at the end of every month is a good thing - hand to mouth here can be precarious if disaster strikes.