First, it is great that you are starting to think about these things and are asking some of the "right" questions. That said, I have a more balanced view as follows:
1) I agree with prior posters - an elite or a good SLAC is one way to go. I also agree that you need to do your homework and make sure that faculty are actively engaged in research. Not all faculty at SLACs do so, and if there are only a handful that are actively engaged in research in may be just as hard or even more difficult to get into one of those labs as it would be at an R1.
2) Another option, in my opinion of equal value, though not without trade offs, would be to attend an R1 or R2 university that has a psychology department with doctoral programs. Though there may be more students seeking out research experiences, there also are more options. I'm in an R2 doctoral department of psychology, and my lab regularly has 20 to 30 undergraduate research assistants and I always have room for bright, motivated, hard working students (nearly all of my colleagues do as well). I've also had students go on to doctoral studies in some of the top programs in various fields of psychology in the country. For example, this year, three out of three students interested in clinical psychology have multiple interviews. I think it helps their applications that they have spent 2-4 years (in most cases) working on a NIH funded project and in a high research activity lab (and spent time in the labs of some of my colleagues as well). My lab also is active in the summer, creating even more opportunities for undergraduate research assistants.
In addition, my university, and certainly others as well, has a program in which the top admitted students can start with mentored research in their freshman year, and receive funding to do so. Similarly, for the honors students in my university and department, it is much more like a good/elite SLAC experience.
At the end of the day, there will be pros/cons to any school you decide to attend. You will want to be a standout no matter where you end up, and you will want high quality research experiences. I would also add that some of those experiences should be a the area of psychology (e.g., developmental, clinical, social, neuroscience etc.) in which you plan to pursue graduate studies.