For my write-up today of The Cambridge History of Judaism, Volume Three: The Early Roman Period, I have two items.
1. On pages 258-259, Raphael Loewe (in "Gentiles as seen by Jews after CE 70") discusses a rabbinic approach to the issue of the Gentiles: "In revealing Torah, God has promulgated the ethical, social and political ideal to be implemented by Israel---as an example, indeed, to mankind: but an example which, as history shows, the world may profess to admire or respect, but will not emulate." My impression from this is that, in rabbinic Judaism, the Gentiles were not to observe the Torah but rather the seven Noachide commandments, and yet they could admire the Torah or even convert to Judaism. According to Mekhilta Yithro Ba-chodesh 5, there is a "universal availability of Torah to all prepared to accept it---hence the divine decision to reveal it in no man's land" (Loewe's words). All could benefit from the Torah, including Gentiles who were not under its yoke, and Gentiles who chose to embrace the yoke.
But Loewe also says on page 257: "The relative rarity of universalistic halakhic exegesis should not overshadow the significance of such passages as the following interpretation of Lev. 18:5, 'you shall keep my commandments, which if a man (sc. any man) does, he shall live'. R. Me'ir assembled an anthology of texts to emphasize their universal and not exclusively Jewish import, including Isa. 26:2, where 'righteous nation' (goy) is understood as indicating an individual Gentile...Me'ir here equates a Gentile who fulfils the law with the high priest himself, and his formulation excludes the possibility that he is presupposing conversion. Fulfilment of the law by a Gentile is...a feasibility that is somewhat less demanding than in the case of the Jew..." Loewe cites Sifra and 'Acherey moth 13, 13 (but I don't know if Acherey moth is a part of the Sifra). Loewe's point here seems to be that Gentiles observe the law when they obey the seven Noachide commandments.
On page 264, however, Loewe characterizes 'Abbahu's position (in Babylonian Talmud Baba Qamma 38a) to be that, "Realizing the Noachides' moral failure, God abrogated their code in the sense that whilst its punitive sanctions stand, fulfilment of its prescriptions (with the consequent merit) becomes, for Gentiles, a voluntary affair..." And Loewe also refers to Yose b. Chanina's view (in Babylonian Talmud Sanhedrin 59a) that the Noachides "revert to the status of idolatrous Gentiles", since the ten commandments displace the Noachide laws that applied to Gentiles, and only the Jews need to observe the decalogue. This is new to me, so I may not be understanding some things here. So I will need to copy this essay, and probably revisit it more than once (whether or not I blog about it).
2. On page 235, Morton Smith (in "Gentiles as seen by Jews after CE 70") states the following: "In the predominantly pagan world of the Diaspora it is likely that Jews, Judaeans, and Ioudaioi often stuck together, overcoming their differences by compromise or neglect. We have little evidence of the requirements for admission to diasporic synagogues; no doubt they differed greatly. We find Philo writing of Alexandrian Jews who thought the commandments allegorical, to be understood, not obeyed (De migratione Abr. XVI.89). Josephus tells us that the first Jewish mentor of the King of Adiabene assured him, 'It is possible...to revere the deity even without circumcision...To be a zealous adherent of the ancestral customs of the Jews...is more important than being circumcised' (Ant. XX.41). But what did such people think 'the ancestral customs of the Jews' were? In Sardis, they seem to have included sacrifice, since the assembly of Sardis gave the Jews there a place to perform it (Ant. XIV.259ff)."
Smith's point here appears to be that the Jews in the Diaspora stuck together, and that meant that they weren't always strict about certain rules. For example, some felt that one could enter Diasporan synagogues and keep the Jews' ancestral customs without being circumcised.