FULL-TIME missionary regulations and guidelines for The Church of Jesus Christ of Latter-day Saints were somewhat different in the 1940s than they are today.
For example, back then swimming WAS allowed (just not with the opposite sex); Saturday was pretty much the universal preparation day back then; missionaries often wore hats; no tracting was recommended on Sunday; and sample door approaches didn’t say “Mr. Smith,” or “Mr. Jones,” but rather “Mr. A,” or “Mr. X.”
Membership in YMCA’s and similar organizations for missionaries was not only legal in 1946, it was encouraged, since not only is recreation necessary, but “may be turned to preaching the gospel.”
If there were enough elders in one area, a team for basketball or baseball was suggested to be formed – and to face local competition.
“The Missionary’s Hand Book,” 1946 edition (and first printed in 1937) is 164 pages long. It was published by the Church Radio, Publicity, and Missionary Literature Committee, of which future President Gordon B. Hinckley, was a key member of.
The Hand Book did not mention going without purse or scrip (not having money, food, nor a place to reside and having to live off the generosity of those you meet). That's probably because that practice stopped in about 1941, at the start of World War II. (Yet, into the 1950s, some mission presidents still sent some of their elders to the country for several weeks each summer to get a taste of what living without means and by such great faith really felt like.)
Some of the Hand Book’s advice is certainly relevant today. However, since sister missionaries were very rare in that era, the entire Hand Book only talks about rules and guidelines for elders.
-“Never call a woman by her first name … Do not touch a woman except to shake hands with her.”
-“Bless, but do not curse.”
-“The missionaries greatest reward from tracting is the humility it never fails to bring.”
-Tracting door-to-door was not to be done on Sunday; and often also NOT on Saturday, if there were other missionary duties.
-“Do not engage in undignified games, sports or pastimes.”
-An occasional good picture show or better still, a fine artistic production, is stimulating.”
-“Remember that you are sent out to preach the first principles of the gospel and to call men to repentance; not to pose as expounders of mysteries …”
-Dress – The Latter-day Saint ministry wears no distinguishing costume, but missionaries should always dress with respect to the the dignity of their work … dark shoes, dark suit, quiet hat …”
-“Sacrament meetings – “…Ushers should always be posted at the door to greet the Saints and welcome strangers.”
-“It is important that missionaries keep up appearances and maintain physical fitness.”
-Notwithstanding a prohibition against swimming with the opposite sex, the 1946 Missionary Handbook also quoted the late President Joseph F. Smith (who died in 1918): "It is not a good thing, neither is it at all wise, for our elders to go out on excursions on dangerous lakes, or streams, or bodies of water, just for fun. They had better stay away. The Lord will protect them in the discharge of their duties."
Thus, missionaries by an early 20th Century admonition, were advised not to run rivers or take any pleasure boating excursions on any “dangerous” bodies of water.