I got the basic structure of the paper with accuracy section roughly done. The aim is to try to share the first draft next week along with some method slides.

This first draft includes three pdf presentations that contain additional notes and comments. I am still working on the references and the summary table. Other updates will come later.

I just read through your literature review, great job! I think there is definitely a place in the literature for a summary/review like this. I've attached my comments... If you want to pursue publishing it (and I hope you do), here a few additional points that I think we'll need to work on:
There should be a section on satellite observations. While the overall focus should be on interpolation methods (as you have done), I think we need a least a short section pointing to attempts to incorporate satellite data in various ways... I've included a short list of potential papers to include. Essentially I think we need to mention the strengths and weaknesses of existing methods and point to the opportunity for 'fusing' it with station data to improve predictions.
I think it would be strengthened by expanding and shaping the conclusion section to be more of a 'suggested best practices' rather than an overview of what others have done. i.e. If there is no single best method, what is your suggestion for completing a project like this? Pick some subset of models, compare them in different places, and choose one best? Or do a family of models and choose the best locally? Choose the best using a suite of validation metrics (which ones?)? I think if you're explicit here about what you think we should do given what you've learned, it will be a much more powerful/useful paper and would set up the temp/precip methodology paper(s) nicely (we could reference this one when describing our methods).