I am only 79 years old, but my wife and I often visit AZ and CA and usually I take my 1.5 watt CW QRP rig. Results from our relatives houses, which are similar to your situation, are sometimes marginally OK, but 80 % of the time when we visit CA, AZ, OR, Norway, the UK, etc. I never even bother trying to operate from the house. I simply walk to a nearby park, hiking trail, or whatever with my battery powered rig and have a blast often making dozens of nice CW QSO's in several hours. It's easy in Europe or the NE part of the US, but even from the Phoenix area sometimes is successful on 40, 30, or 20 meters. Noise level is near zero once you are a few hundred meters from civilization. Propagation is not nearly as favorable as it was a decade or more ago, but still not hopeless near the bottom of the cycle. SSB will be more difficult with low power than CW or digital, but some folks have had some success with 5 to 15 wats and compromise portable antennas. I would do some listening tests before spending big dollars. As Zak suggested, get your antenna away from houses as much as possible. Even going from 1 foot to 8 feet away may make a significant difference in RX noise. On a nice day you could even take your rig outside and hook a temporary antenna right to the antenna terminal for RX noise tests. If you can find a place where you can receive OK, then you can think about the TX problem. With two houses so close to and probably absorbing much of your TX energy, it does not look promising, but strange and unexpected things do happen. First of all a 10 foot vertical with a remote ATU right at the base of the vertical, even with your radial system, should tune and radiate OK on 20, and better on 15, 17, 12, and 10 meters. If you could make the vertical part a few feet higher 20, 17, and 15 meter performance should improve. I am concerned about your present set up. The horizontal 6 feet is right next to the light string which goes into the house. There is a high probability that noise pick up from inside the house, rather or not the string is plugged in, is coupled to your antenna. Why not stop the active light string a few feet before it reaches the end of your wire, then just use a fake not hooked up light string in parallel with your 6 foot wire. Now you have a 16 foot radiator which with a remote ATU which should at least tune up and radiate well on 14 MHz and higher, and may even tune up on 30 and 40 meters, just read the ATU info and it should tell you what the minimum length of wire is recommended for each band. If you can get a total length of about 26 feet (10 vertical feet and 16 horizontal) I have found it works well on 20, 30, and 40 meters, (at least out in a park away from buildings). Remote ATU's have some loss, but many hams find them very useful for at least being able to match many non resonate wires. I am not recommending you jump into buying a remote ATU until you do some more investigation. I am sure that for many more years when we visit our kids and grandkids in many states and countries, we will continue to walk to a park and my wife will read, knit, or work crosswords while I operate QRP CW. It is a bit tough in AZ in the summer, but still possible for a few hours in the morning, and even northern Norway and here in Alaska in the winter, is still possible some days for a few hours with lots of winter clothing. Due to poor propagation, I finally retired my 1.5 watt QRP rig for an Elecraft KX-2 which puts out up to 10 watts. If you have not tried CW, a 5 watt rig works at least as good as a 100 watt SSB rig. Rick KL7CW