The sensitivity to the amateur/professional line certainly makes sense. And it helps to partially explain why the bulk of Travis' work in the beginning of his design career was localized. Why would he take on the expense of travel for a project he wasn't going to get paid for? It helps to explain why he would refer to Barker projects like Waverley and Spokane and even the work Barker undertook in Ohio. I'm of the mindset that there are other reasons why Travis didn't want to take on these kind of projects, but I do think the travel and expenses (and what it might mean if they were covered by others) were a factor.
It was Barker who was going out to the sites, examining them for suitability and staking out the courses. And those two steps often went hand in hand. Sometimes another player had already passed on the suitability of a site. In many cases it was someone like Bendelow, who would stop in at a club on their request for a day or two simply to give this kind of advice.
There was a marked shift in how courses were built around World War I. Donald Ross had a lot to do with the practice of the contiguous design and build process, where an entire course was plotted on paper before construction began. Prior to that time, and as we see on many of the projects listed on this thread, the first steps were to route a course, clear the land and grow grass, with bunkering and fine tuning seen as a down the line second process. Often times hereabouts the fact that a course underwent tweaking in its early years is seen as some kind of criticism of the original design, when in fact it was part of a longer term plan for its development. This paradigm shift helps to explain why preconstruction plans became the norm, and the Oakmont model of adding bunkers after observing play went by the wayside.
As design moved further into the Golden Age, the process changed and you saw more and more projects where routing, bunkering and fine-tuning where treated as one process. Part of this probably had to do with a shift in the economics of course construction, and part had to do with the expertise that the architects in America had developed. CBM was already heading in this direction prior to the war, and you could say that Colt and Ross were doing the same with the way they developed their plans either in concert or working on their own. In a few years, you'd have guys like Langford taking the a design plan to perhaps its highest art as he laid down the roadmaps for the construction teams of American Park Builders.
In some sense, Barker was always part of the old school. As we discussed, there really aren't any Barker construction plans out there, as I don't believe he ever worked that way. His routing work was done in the field, and if he was going to bunker a course, it was after the preliminary work was completed. One has to wonder if his practices would have changed if he'd remained in the States, a question for which we'll never have an answer.
With respect to Barker's body of work, i think it makes sense to view each project in light of what he was hired to do. At places like Waverley, Spokane, and New Orleans, he was providing the framework for the club's to get started on their courses, as he was not going to be returning to oversee the further development. On projects like Springhaven, Detroit and East Lake his advice was limited to specific aspects of the course. And then there are the bigger projects like Rumson and Roebuck where his role as both professional and architect involved a more intensive engagement with the long term development of the course. Other projects like Columbia, CC of Virginia and Belle Meade might fall more in a middle ground, where his work might have been seen as more than just a one-stop routing project. At Capital City and Raritan Valley, he had roles in the initial work and work that took place a few years later.