What to look for in a site planning surveyor? Mixed Use Property

[Faye R.]

Should I just google local surveyors and look for the best reviews or is this one of those things where, assuming that they are properly qualified, I can select the lowest price? If so, is it enough that they are certified with the state (Oregon) or are there other qualifications that I should require? Will the surveyor know what to include in the survey or is it my responsibility to consult with the county and inform the surveyor? 

Thanks in advance! 

Details that may or may not be relevant: missing pins, corners are not 90 degrees, ground is slightly sloped, original existing structures predate planning dept records and likely infringe on neighboring lot. For now I'm developing an unused portion of one of two adjacent lots but I will eventually want to add density to the developed portions of both lots so I'm thinking that it makes sense to survey both of them at once.