For avoiding rowwise(), I prefer to use map() in mutate(), because for rowwise() there will be an unnecessary grouping creates.
set.seed(123)
data_frame(set1 = 1:10, set2 = 11) %>%
mutate(rand_btwn = map_int(map2(set1, set2, seq), sample, size = 1))
## # A tibble: 10 x 3
# set1 set2 rand_btwn
# <int> <dbl> <int>
# 1 1 11 4
# 2 2 11 9
# 3 3 11 6
# 4 4 11 11
# 5 5 11 11
# 6 6 11 6
# 7 7 11 9
# 8 8 11 11
# 9 9 11 10
# 10 10 11 10