First thing in the day BEFORE starting press the primer head plunger, there should be pressure there, if it take some pumps to restore pressure it suggest a perished diaphragm in the head.
Does the van turn over slightly slower than you'd expect ?, these are starting to suffer from a high resistance on the solenoid switching wire from the ignitoin switch, done one not so long back, this had had a new battery and starter before he came to me, took me a while to find as someone had half crimped a connector on the lead, with half the strands missing then heat shrunk over it, new soldered terminal with heat shrink good as new, first time starter even in the recent snow after being left 1 week, had 160,000 miles on it.
tabetha