In your shoes, I would find out my credit score from a couple of free sources. A lot of credit card companies offer credit scores and Credit Karma offers one as well, although that score is from a model mortgage lenders don't use. Get the score and the model used by the source for several. Then start contacting lenders. For preliminary shopping, the lender does not have to pull your score. Tell the lender your various scores, the source and the model used. They will make an assumption based on that information to give you an estimate.
Once you have narrowed down the list to two or three and you want to write the offer, have the lenders pull credit and do a pre-approval. Use that in your offer. All hard pulls in a 30 day window that are for a mortgage are treated as one, so as long as the lender reports the request as for a mortgage, your score should not drop by much.
You should be able to shop around in a day and have a pre-approval quickly. If you are easy to underwrite, i.e. W-2 income, low debt to income, and a high score, consider using a no-frills online lender. Aimloan.com has a good reputation, although I have not used them. Pricing has very favorable when I have checked them.