Moving to Dalat

I would (and did) keep it simple. Get a 3 month DL tourist visa at a consulate or through a visa-on-arrival website. Even with longer business visas, you will have to leave and reenter the country every 3 months. After you are here and your new life is working out, you can consider your long term options. Either repeat getting new 3 month visas via an overnight visit to Phnom Penh (bus or plane) for example, or hire a visa agent like Sunviet Travel or equivalent in Da Lat who can wangle longer business visas.

If you get married, its a new ballgame. You can get a 5 year Visa Exemption Certificate (VEC) and Temporary Residence Permit (TRP).
You sound like an optimistic person with marriage in mind: search the forum for "marriage" and "moving" for tips, and bring any divorce papers you might have lying around from your last marriage, original documents.
Just in case of course - but don't jump into anything too fast! 

gobot wrote:

Just in case of course - but don't jump into anything too fast! 

As Gobot said.  In fact, I would say don't jump at all --- approaching every relationship as s-l-o-w as you can.   A good woman will still be there a year from now if you and she both are sincere and serious about one another.  Good people and good relationship aren't limited-time offers that you'll need to act fast before they expire.

Thanks!  I take your advise (since relationship is very new and hasn't really been tested yet) and get a 3 month tourist visa until I see how things pan out.  She's 52 and I'm 66 so were not that far apart and our basic goal is the same,  long term compatible relationship.  Maybe marriage down the road if we are good for each other.

Your right Ciambella.  My mantra is "slow down".  Take it slow and easy.  One step at a time.