I did start at 5! And stopped about 10mins later
I am up for it, but don't have a whole day to spare for a while. I think though, going by just the 3 I did this morning, that if you did want to do all in one go and not get a disappointments of caches missing, then the series would need tackling very soon.
All 3 I did were 35mm type. One was affixed in place very well, one was so so, and one I think could just get blown away or otherwise lost quite easily. The walk as a whole I think would be very nice though, as I have been on parts of it for non-caching reasons previously.