The Authority has narrowed down the alignment through Riverside, and that pretty much means downtown is not an option. The Watkins Drive station (originally proposed by the Authority and shot down by neighbourhood groups) was withdrawn as well, but another station that I hadn't heard of- the Martin Luther King Blvd. station (at MLK/Chicago) got shot down. The two stations under consideration for the Riverside area are Corona (at Cajalco Road near the Dos Lagos shopping centre) and March Field (at I-215 and Alessandro Blvd.). The main factor to decide between the two will be whether the I-15 or I-215 alignments are chosen.
The thing is that other station options in the San Gabriel Valley were rejected for poor intermodal connections or unsuitability for TOD. The only reasons listed against the MLK option? "City and UC Riverside support March Field." The defense for March? You guessed it- "City of Riverside and UC Riverside expressed a preference for this site." Oh, and it's got easy access from the freeway- 'cuz don'tcha know that's what matters out here?
Even the Temecula-Murrieta station is being chosen based on intermodal accessibility- to the point that, at some times of day (commute hours), it'd be easier for me to get to the proposed Murrieta station car-free than the Riverside station. (A quick bike ride/walk/2 stops on the 16 to lot 30, then the 208 straight to HSR vs. 16 downtown to connect to 22 to connect to 20, all local and the latter two only hourly.) Probably easiest for Riverside transit riders will be the San Bernardino station, located at their new downtown transit center, with easy connections on Metrolink and Omni 215.
CAHSRA, City of Riverside, UCR... all I have to say is fuck you very, very much.
(EDIT: Sorry, in my rage I forgot to tell you that the Transit Coalition has the alignment analysis for your perusal.)