It is indicated here that they could construct residential facilities only up to the bank of Gaṅgā, not further.

NOTE. This entire chapter is a fine illustration of how one should employ one’s talents, skills and energies in the service of the Supreme Personality of Godhead. This is indicated by the expression mat-karma-kṛt in Bhagavad-gītā (11.55) which implies that one should work for the Supreme Personality of Godhead.

How one can work for the Supreme Lord is explained by Prabhupāda thus:

As far as work is concerned, one should transfer his energy entirely to Kṛṣṇa conscious activities. As stated in the Bhakti-rasāmṛta-sindhu (1.2.255),

anāsaktasya viṣayān yathārham upayuñjataḥ
nirbandhaḥ kṛṣṇa-sambandhe yuktaṁ vairāgyam ucyate

No work should be done by any man except in relationship to Kṛṣṇa. This is called kṛṣṇa-karma. One may be engaged in various activities, but one should not be attached to the result of his work; the result should be done only for Him. For example, one may be engaged in business, but to transform that activity into Kṛṣṇa consciousness, one has to do business for Kṛṣṇa. If Kṛṣṇa is the proprietor of the business, then Kṛṣṇa should enjoy the profit of the business. If a businessman is in possession of thousands and thousands of dollars, and if he has to offer all this to Kṛṣṇa, he can do it. This is work for Kṛṣṇa. Instead of constructing a big building for his sense gratification, he can construct a nice temple for Kṛṣṇa, and he can install the Deity of Kṛṣṇa and arrange for the Deity’s service, as is outlined in the authorized books of devotional service. This is all kṛṣṇa-karma. One should not be attached to the result of his work, but the result should be offered to Kṛṣṇa, and one should accept as prasādam the remnants of offerings to Kṛṣṇa. If one constructs a very big building for Kṛṣṇa and installs the Deity of Kṛṣṇa, one is not prohibited from living there, but it is understood that the proprietor of the building is Kṛṣṇa. That is called Kṛṣṇa consciousness. If, however, one is not able to construct a temple for Kṛṣṇa, one can engage himself in cleansing the temple of Kṛṣṇa; that is also kṛṣṇa-karma. One can cultivate a garden. Anyone who has land – in India, at least, any poor man has a certain amount of land – can utilize that for Kṛṣṇa by growing flowers to offer Him. One can sow tulasī plants, because tulasī leaves are very important and Kṛṣṇa has recommended this in Bhagavad-gītā. Patraṁ puṣpaṁ phalaṁ toyam. Kṛṣṇa desires that one offer Him either a leaf, or a flower, or fruit, or a little water – and by such an offering He is satisfied. This leaf especially refers to the tulasī. So one can sow tulasī and pour water on the plant. Thus, even the poorest man can engage in the service of Kṛṣṇa. These are some of the examples of how one can engage in working for Kṛṣṇa.