Two couples will be in wine country for 2-3 nights, probably basing in Laguarda. From there, what is the best non-car transportation to BCN and where do we get it?
Also, I've been trying to find a local guide who will meet us in Laguardia and spend a day taking us to 2-3 interesting wineries. So far no luck. We would also consider a guide who would drive us to Laguardia from San Se, tour for that day, and leave us there. The ones I've seen are not affordable (e.g. E 350-E 750 per person). Would welcome any suggestions/referrals.

You can check with Thabuca Wine Tours regarding both small gourp tours and private tours (https://winetoursrioja.com). It's not inexpensive but doable. Finding a car and driver in the Rioja is not easy if you are trying to do it on your own. There just are not that many available. If you do end up trying to do it on your own, you will have to make reservations at all of the wineries you want to visit, with only a few exceptions if you want to do is sip some wine. A few of the wineris have wine tasting bars, but even some of those require reservations and all open liminted hours. If you don't speak Spanish, that limites how man wineries and which ones you can visit on any given day.

You can take the train from Logroņo to Barcelona. The trip take between 4 and 5 hours, depending on which train you take. Buses are also available and take around 6-1/2 hours (ALSA.com) to make the trip.