The longest 'conventions' I remember were 8 days. In those days, they would typically start at 9 or 9:30 in the morning and end at 9pm except for the final day which was 5 or 6pm. It probably ended at 5 but after the final long winded prayer, it was so much later. As a child, the convention seemed to last forever and the final prayer was an act of torture.
Larger conventions were usually a distance from home for us. I can recall one being 300 miles away in Ottawa but there were a few that were about 110+ miles each way, over the border well into Buffalo, NY. The Buffalo ones went to 9pm and as there was a shortage of accommodations, we drove each day in August heat with no A/C while fully dressed for the 'program'. By the time we were home, it was midnight only to be up again early (5am) the next same day to do it all again.
As there wasn't enough parking at the convention site, we sometimes would park in Fort Erie and take one of W/T hired school bus shuttles the remaining distance to the convention.
One time, when we were driving the entire distance, we gave a ride to a visiting Sister that was originally from Bahamas or some other tropical location. At the border, she wasn't permitted entry into the USA as she didn't bring along the required documents so we left her there and carried-on to the convention. I don't recall what became of her.
Later there were a few international conventions at the Olympic Stadium in Montreal. Although in 1984 there was a more local one held in London, Ontario, we were good and obedient lemmings and attended the one we were assigned. What hell that was.
Anyone remember the big 'THRILL' of seeing other cars on the highway that displayed YHWH or had a 'Watchtower' taped to the rear window?