Running a SQL Server query with as little impact as possible
It rather depends on what the scripts are intended to do...

If you can cope with the occasional dirty read or unrepeatable read issue (or they are truly simple enough that these are unlikely/impossible), also set your transaction handling to the most lenient mode possible with SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED. This is actually equivalent to WITH(NOLOCK) but covers the entire connection going forward instead of just the one table. There is also SET TRANSACTION ISOLATION LEVEL SNAPSHOT which generally stops your query from blocking other concurrent transactions without the risk of dirty or unrepeatable reads, but that does have some potential IO impact on tempdb.

If your queries are making any updates to the database then note that WITH(NOLOCK) support is going to be removed from UPDATE and DELETE statements at some point (see https://technet.microsoft.com/en-us/library/ms187373.aspx).