If you're doing HART I can recommend MacTek's Viator HART modem, available for either USB or serial.
I like the utility the checks the HART connection and displays a the primary PV.
For low cost programs, there's two that I'm aware of.
1) I just became aware of "Pactware", a Windows program used heavily by the German instrument manufacturers, E&H, OhmartVega, Krohne, etc. It appears that it uses 'DTM' as a device specific file, rather than DD's. It is not apparent what the communciation link is, it might be HART, because the instruments are all HART.
Appears that downloads are free and that it is not licensed. Ohmart serves it from here:
I have not installed or used it.
2) Siemens single point PDM program is about $100. I have used it. It needs a HART modem to talk to the instrument on the 4-20 loop. Single point has full functionality, but it only does one setup (saveable, restoreable) at a time. To do another, close it down and open it up again.
PDM is a huge install, being only a fraction of Simatic Manager, but the entire Manager is apparently installed (about 30 minutes install time from a CD on a laptop).
I found I had to read the installation instructions point by point, it demands a particular install sequence.
It uses the dreaded floppy license and I've lost a license when a laptop died, because the license couldn't be retrieved from the laptop harddrive. Hazard of using Siemens.
The operation is Teutonically non-intuitive and frustrating in the connection phase: picking the port and the instrument. There's something called a 'lifelist' that is supposed to assist in connection, but I've never figured it out. This might disqualify it for your requirement of simplicity. I have a sheet of notes indicating where to right click, where to double click, where to open and click, ya-da, ya-da, because I forget, too.
The HART configuration part is all menuized for easy navigation.
Be sure to get a current version V6 (up to SP3). The older V5 does not upgrade to V5.
DD updates are slow to come out, about annually(?). HART Foundation has to release them, then Siemens has to do whatever to convert them, then they have to filter down the distribution chain. True trickle down theory (that's a US joke).
Dan