I also ran before gels (mid-late 70s), but I did like to get (the original) Gookinade during a few marathons. I did also drink water but never too much at once and I did not like to stop or even slow very much. I did not drink in the last several miles (why bother), and always ran the last 10k at close to my average race pace (twice faster, twice slower) but within 5-10 sec/mile. My long training runs rarely involved drinking.
I have a bit of trouble with gels and the like when on long rides if I am riding very hard (22+mph) and prefer drinking Gatorade (Endurance is best) made up a little weak (I take powder and mix when getting water during rides). Some of the 'pro' mixes do not sit well with me and I am not racing marathons now or I would experiment more to find the right mix for myself. I ran moderate temp marathons (mainly during the southern CA winters, with starts between 7 and 8am).