That does sound easier. I'm sure I have a few mini USB leads around too. Just over £2 for an unsoldered board. I might order a couple of them and wireless modules and maybe some temp sensors too. If I had more time I could get carried away with these.
Had a quick look on Google. Depends how much current the board will be consuming. If it's not doing too much it should be ok with the 18V, otherwise it would need another regulator that could handle tthe current.
The Pro Minis (without USB) need a USB to Serial (FT232) adapter of some sort to program them.
Because my adapter doesn't have the correct reset pin or something like that it's a pain to use, I've got to reset the board at exactly the right point to get sketches to load.
A little graph of the temp monitoring using a LM35. The temp at the start was in my bedroom, dropped when I brought the laptop into the kitchen. Went back up with the oven on. The drop down to 6°C ish was when I put two frozen peas either side of the sensor.
I have quite a few things on the way from China <twiddles thumbs>