I seem to remember a mention of Warsaw roads/streets in Adam Zamoyski's book titled, The last King of Poland.
It was probably there where I once read the information on the extremely bad state of roads between Warsaw and Kiev towards which king Stanislas Poniatowski travelled to meet Cathrine II of Russia in a boat on the Dniepr river, the then Polish-Russian border river, in the 1780s. The wheel axes of the royal coach crashed twice during the journey under the monarch due to this deplorable state of roads.
The subject of the roads in the 17th century is strictly connected to the subject of the Royal Mail which was organized in Poland in 1588 on the orders of king Sigismundus Augustus. Prosper Prowana, an Italian in the king's service, became the first director of the institution. Then king Augustus II issued a bill in 1717 in which he outlined the trajectory of the postal routes in Poland and also the book of instructions. An interesting account of the Warsaw-Vilnius route across centuries can be found here (in Polish):
The time of travel for mail between the two Polish Commonwealth capitals: Warsaw and Vilnius, was set for one week.
I think perhaps your best source of information (potentially) would be the memoirs and diaries of military persons such as Hetman Zolkiweski, JC Pasek and so on
An excellent source, collecting accounts of foreign people visiting Poland, however referring to the 18th century, would be a two-volume book "Polska stanisławowska w oczach cudzoziemców
" [Stanislas August's Poland in the eyes of foreigners], Warszawa 1963. That is the work I often came across as a source cited in different history books I have read.