Speaking of books, I also bought a Rumantsch dictionary (rm–de/de–rm; specifically, Rumantsch Grischun).
It's got a little mini-grammar at the end, which may come in handy.
What I'm disappointed about, though, is that the words do not have any pronunciation hints with them.
While the orthography is phonemic enough in general, there is at least one point, possibly two, where letters are ambiguous: e and o can be either open or closed (at least according to some sources; the Wikipedia article and the dictionary pronunciation guide disagree); and sch can be either voiced or voiceless.
While the French Wikipedia article on RG helpfully says that you can usually guess which it will be if the word has a cognate in French (depending on the sound in the appropriate position of the French cognate), I would have hoped that, if not all, at least the words with sch in them would have a pronunciation guide so that one can know that, say, sche (fr si) starts with /S/ but schanugl (fr genou) with /Z/.
On a slightly-related not, I seem to recall reading somewhere that Rumantsch has, coincidentally, roughly the same phoneme inventory as Croatian.
It's certainly got the distinction between č and ć (e.g. la tschatta chatta "the paw finds", pronounced "la čatta ćatta") and it's also got đ (but not dž), lj and nj, as well as š and ž (represented by the same letter, unfortunately—either sch or, before certain consonants, s).
Hm, they do look extremely similar, especially the consonats; the main difference I can see is that RG has a schwa and an eng, while Croatian has /x/ and /dZ/, and that Croatian's /v/ is said to be an approximant while RG's is said to be a fricative (like both languages' /f/).
Hm... that means I should be able to write RG in Croatian orthography, or Serbian cyrillic :) Fun!
(Schwa can be "e/е" and eng can be "ng/нг", as in the regular RG orthography.)
So the example text used in the German Wikipedia article to compare the five literary idioms and RG would go like this in Serbo-Rumantsch:
Ла вулп ера пушпѐ ина ђада фоментада. Ква а елла вис син ин пињ ин корв ке тењева ин ток ћажијел ен сес пикел. Квај ма густасс, а елла пенса̀, ед а клама̀ ал корв: "Ће бел ке ти ес! Ше тес ћант ѐ ушѐ бел шко тиа парита, лура ес ти ил пли бел учѐ да тутс."