How does rho-dependent termination occur?
There is no dichotomy in the two sources you have described. The text book you linked to says, exactly (emphasis added):


  Rho appears to bind to a stretch of 72 nucleotides near the 3'-end of the nascent RNA...


It doesn't say at the 3'-end, which is obviously impossible since the 3'-end forms a double-stranded hybrid within the transcription bubble. 
Rho is not loaded at the 5'-end of RNA, either, but rather binds internally at cytidine-rich Rho utilization (rut) sites, which will be somewhere 5' of the actual point of transcription termination. As you mentioned, there is a lot of uncertainty in the process and, while a lot is known about rut sites, as far as I can tell there is no consensus sequence, thus making it difficult to systematically identify rut sites throughout the genome. I have found papers which identify rut sites in the 5'-UTR (1) as well as within the 3'-UTR, intercistronic regions and coding sequences (2, 3, 4).



Mechanism of internal Rho loading:



Koslover DJ, Fazal FM, Mooney RA, Landick R, Block SM. 2012. Binding and Translocation of Termination Factor Rho Studied at the Single-Molecule Level. J Mol Biol 423:664-676