Hi! I saw this post last night and was intrigued... I thought that I had already won against my sister using low-point tour plans, but when I went back to the game results it turns out she had also taken the low-point tour plans (I had 20 & 30, and she had 30 & 30).
SO! Today I tried it in a game against leo_myself (another GoGoa 'guru' who was slightly higher ranked than I)-- I told him I'd seen in a forum someone ask if anyone had won this way, so I was going to try to test it. He laughed and wished me good luck.
Retrospectively, I think one important thing to consider is the placement of the destinations. Often you can pull two 40 point tour plans that have overlapping destinations (for example: I've played one with two overlaps, where I only needed four unique destinations). In this case, the two 40-point tour plans leo_myself had did not have any overlaps, and were actually fairly spaced out. My two 30-point tour plans, on the other hand, had one overlap, giving me a distinct advantage on that front.
Having overlapping destinations therefore gives you more turns to explore your destination 'type' combinations. It seems the hardest to try to get all 6 of a kind, so I was focusing on getting sets of 5. I completed two sets of five types of destinations, and since our last two rolls were really awful I did not make it to the Dudhsagar Falls +20 scenic location, but was still able to get +20 points by visiting a third holy site.
In the end, he was not able to finish one of his tour plans, so I won 240-200.