Its only been a month, that's not too old right?
I have been working on my commercial after nearlly 20 years of flying. When I read 61.129 I was also puzzled by the requirements of dual on the 100nm XCs and sole occupant on the long XC. After doing the dual XCs with a CFI - I realized that I had not been on an XC with an instructor since my instrument rating - 15 years earlier. The CFI had some good insights and it was worth while being dual. The only explanation for being sole occupant I ever read on the long was so you could demonstrate you could manage the entire flight without anyone helping. Even a passenger can help hold charts or get something out of your reach. I guess it is good prep if you are going to be a future freight dog flying alone on those dark and stormy nights.
The dual 100NM XC's seem weird but I do agree they are good. For most people, once they get their PPL, they dont do any more Dual XC's so they never log a XC in which they are both receiving Dual and PIC. This is particularly true for the night flight where most people log the single night Dual XC they need for the PPL and that's it. There is a higher chance of logging more dual xc time during the day both prior to your ppl and after.
As to the passenger idea for the 300NM, I recognized the possibility that sorting papers and handing you things are indeed helpful and I guess the language of the regulation would be too complex to say something along the lines of the passenger not being allowed to act in any capacity except there to ride along. I would have liked to have seen the CFI extended to more than just a CFI though but I guess the "simulated solo/ride-along" language most of us apply to the regulation isn't actually there either and technically speaking the regulation doesn't say the CFI cannot assist in any capacity.
An additional pilot could comply with all the "simulated solo" requirements and just be along for the ride (and serve as a distraction) without offering any assistance and it would allow 2 pilots to complete the requirement on a single trip. It's just weird that the FAA trusts us to log the flight as we see fit but doesn't trust us to abide by a "simulated solo" rule in which any passengers or additional crew are not allowed to assist with the flight, unless the simulated solo is signed by a CFI. Of course if you were one to abuse the FAA's trust, there is nothing stopping you from taking passengers or another pilot on your long cross country and claiming it as solo, though that'd be a violation of the few rules the FAA does have on logging (specifically logging solo time when you are the sole occupant) and would be a violation of the experience requirement for the commercial license thereby jeopardizing your commercial license.
The commercial solo xc can be done in 1 301nm flight. Nothing says you have to return to the destination, or can’t pick up a passenger/Cfi, etc. just log the flights appropriately. It’s also the only requirement that really make sure you can plan a trip outside if your semi local area.
For the day/night dual. Fly 101nm for 2 hours in the day, eat, return at night and knock that out. But given the 2 hr minimum you might as well go farther and learn more.
The day/night one isn't a big issue as noted, because most people end up doing it as a single trip out during the day and back after dark. Even at 100NM and 2 hours its not a huge issue. I did mine in 2 separate trips (more because I already had a sufficient dual day xc completed) which allowed me to do the night cross country at 105NM (210NM roundtrip) in a Piper Arrow in 2.4 hours with some night currency landings thrown in for good measure. Sure if I had planned it as an out an back trip, I probably would have been about an hour short of the 2 hour requirement but as you said, I'd probably just go plan to go further (or fly a slower airplane).
Yes, the solo xc can be done in a single 301NM flight but how many of us have a plane that doesn't need to be returned to base/home and/or needs to make a one-way 300 or more NM flight? Short of you relocating or buying a plane and ferrying it home yourself, most of us wouldn't have cause for such a one-way mission. That being said, there are other ways of getting that distance or more on various missions that might make more sense but that can be a bit of a toss up depending on the particulars of the plane. Planning a weekend (or longer) vacation out of it is certainly a viable mission if you own the plane and may be viable if you rent (depending on the rental policies and overnight charges the rental operation charges) but its still not a trip most of us would typically meet inherently as a function of our normal flying; its one that for most, requires a plan specifically geared towards meeting the requirement in question.
