Dating Paul's letters without reference to the date of the Crucifixion

To what extent is it possible to set constraints on the dates of Paul's letters without reference to the traditional date of the Crucifixion? Are there studies out there that discuss this?

1 Thessalonians is usually regarded as the earliest of the extant Pauline letters, based on matching up the itinerary described in chapter 3 with the itinerary described in Acts. However, in the things I've read on the dating of 1 Thessalonians, the most common date cited -- 49-51 -- seems to be determined by reference to the dating of the Crucifixion to 30 or 33 CE. The argument, as e.g. presented by Ehrman here, goes:

• ca. 30 CE: Crucifixion
• ca. 31 CE: conversion of Paul
• shortly afterwards: Paul travels to Arabia and then Damascus (Galatians 1.15-17)
• ca. 34 CE: three years later he visits Jerusalem (Galatians 1.18)
• ca. 48 CE: fourteen years later he visits Jerusalem again (Galatians 2.1)
• shortly afterwards: Paul goes to Thessalonica and then Athens, and then writes 1 Thessalonians (1 Thessalonians 3.1-6)

However, the 30 CE (or 33 CE) date doesn't appear in the record until much later: we don't see it attested until 200 CE, in Clement of Alexandria and later writers. Irenaeus, for example, thinks the Crucifixion happened in the late 40s CE.

Hence my question. Are there chronological constraints that can help pin down Paul's dates that don't depend on the traditional date for the Crucifixion? What would be the best published studies along these lines?