(A few comments on what the Kollel wrote in their Insights to Daf 21:)
1) On water fit for man:
The gemara , 21a, says that in Bovel they also used the heter of Pasei Beiroyos because they went on Shabos to learn Torah in Botei Midrashos. Yet, I suppose, that they didn't take their animals along. But the gemoro now atates that the only time that a man can drink the water is while his animal drinks ( according to Rashi) or because his animal can drink ( according to Tosfos). Did they really take their animals along in Bovel to learn Torah ?
2)On The size of the Torah:
On the Mahadura Basra on the Maharsha which you so beautifully explained , maybe that explains why the Later Sages are associated with the Heichal , which has more kedusha than the Ulam, which is associated with the Earlier Sages; The reason can be, according to the Maharsha, because the 2 first parts of the Pardes, pshat & drash, which the Later Sages understood, are more essential than the two next parts, Remez & Sod, which only the Earlier Sages understood. Just a thought.
30) On The Enactments of Shlomo Hamelech:
Thank you for another Gevaltig Vilna Ga'on. Our Magid Daf Yomy in NY ( Rav Chayim Wilner) commented: To create Issurim deRabonon, like not to carry in a Movuye or in a shared property, or not to walk more than 2,000 amos outside the city you need a Rav with great Yiras Shomayim, but he doesn't need to be a great Chochom. However, to create these same issurim but create with them the solutions, such a person is a Chochom mikol Odom, Shlomo Hamelech.
1) It seems that they indeed traveled upon their donkeys, as that was one of the only means of transportation in those days.
2) A very nice thought -- thank you!
By the way, we saw recently another explanation why the earlier Sages are compared to the opening of the Ulam, and the later Sages are compared to the opening of the Heichal. The Maharal says that the width of the opening of the Ulam (20 Amos) is twice the width of a normal Pesach (10 Amos), as described at the beginning of the Masechta. The Gemara means to say that the earlier Sages had two openings , as it were, through which they absorbed wisdom -- one, their Sechel (Neshamah), and two, their Guf, since they were so holy that their Sechel dominated their Guf and subjugated it to its will (Ruchniyus). On the other hand, the later Sages are compared to the opening of the Heichal which was ten Amos wide, a single Pesach. They were unable to subjugate their bodies to their Neshamos, but they were nevertheless able to maintain their Neshamah on such a level that they could absorb Chachmah through it, so they had only one Pesach for Chachmah. We, though, are compared to the eye of a needle, because our bodies dominate our Neshamos, so we do not even have a single Pesach for Chachmah.
3) Another very nice thought -- thank you!
The Rambam in his letters described how he went each day on his donkey from the Jewish quarter to the palace of the king. That is many hundreds of years after the Gemara.