In chapter 66, St Benedict describes the monastery:
If possible, the monastery should be arranged in such a way that everything necessary — in other words, water, the mill, the garden and the various crafts practised — should be inside the monastery, so that the monks do not need to go wandering outside, for that is not at all good for their souls. (trans. White, p. 107)
Monasteries are not meant to be tourist attractions or places that are easily left. From its beginnings, monasticism was a retreat from the world, even if in practice the grace of God kept the monks from having outside contact. The Life of Antony from St Athanasius was a story of him moving to progressively more remote and inaccessible places, ending at ‘the inner mountain’. In Gregory’s Dialogue 2, we read of Benedict fleeing to become a hermit because of the dissolute life he saw at Rome.
The cloister is part of this withdrawal. It is an architectural feature that is inherently inward-looking. I suspect it is descended from the peristyle of the ancient Roman domus, but its function is not simply to provide shade from the head or dry from the rain but to connect together as many of the buildings and rooms of the monastic complex as possible — oratory/chapel, dormitory, chapter house, refectory, library, infirmary.
Nevertheless, Benedictine monasteries, self-sufficient though they are, cannot be totally cut off from the world. They interacted with the world in several ways. First, they provided hospitality to visitors. Second, they provided care and assistance to the poor. Third, they sold the produce of the monastery to provide for themselves. Fourth, in practice (that is, not according to the ideal in the Rule), many Benedictine monasteries became places of community worship.
The purpose of the monastery, nevertheless, is to provide a haven from the distractions and care of the world, a place to seek hesychia and to find God’s grace that will calm the human heart to teach it how to pray, providing time and space for meditation on Scripture.
To this end, monks who journey (ch. 67) must say nothing of what they saw outside. This is like idle chatter and idle curiosity. It is not the business of monks.