At this stage it is too early for any attempt at translating this text in Small Santiago Tablet (which, though, I presume is a calendar covering the year).
A few general remarks may, however, be useful:
1. There are not many glyphs in the three here presented calendars (week, month, year) which recur often. Consequently we may rule out the possibility that the glyphs are components of an alphabet (either as 'letters' or as signs corresponding to syllables).
Alphabetic signs might on the other hand perhaps be there anyhow, as small signs of different types e.g. those often hanging under an elbow. But such signs are not frequent enough to carry much information.
2. What could we expect to read in a calendar? Take as an example my almanac for 2004. I can find notes about where the cardinal points are. Spring equinox, Midsummer, Autumn equinox and Midwinter are there. But I cannot read anything about their meaning. I don't need that. In Sweden, e.g., Midsummer is an important holiday and all the memories and events connected with that date arrive in my mind as soon as Midsummer is mentioned. Consequently we cannot expect more than short notes - not really texts - in any calendar.
3. Presumably, therefore, the reader of a rongorongo text must be capable of recreating the meanings connected with the texts (at least those parts which are in calendars).
In the Mayan book Popol Vuh there is described two ways in which the text may be read: First of all just to refresh the memory about some detail (similar to when I look in my almanac to locate an important date) and secondly to recreate the whole system in which the events are embedded - a reading which will take very long time.