At what altitude, if any, may an ultralight overfly the Gallup airport (KGUP) with no prior authorization without violating FAR 103.17? At what altitude, if any, may an ultralight overfly the Gallup, New Mexico airport (KGUP) with no prior authorization without violating FAR 103.17?

This is a question about the meaning of 


  "within the lateral boundaries of the surface area."


Resources-- 

FAR 103.17 -- 


  "No person may operate an ultralight vehicle within Class A, Class B, Class C, or Class D airspace or within the lateral boundaries of the surface area of Class E airspace designated for an airport unless that person has prior authorization from the ATC facility having jurisdiction over that airspace." 


Sectional chart depicting KGUP

Description of the E2 airspace at KGUP-- from page E-116 of the FAA's "Airspace Designations and Reporting Points" document FAA Order 7400.11D-- 


  "ASW NM E2 Gallup, NM
  Gallup Municipal Airport, NM
   (lat. 35°30'41"N., long. 108°47'15"W.)
  Gallup VORTAC
   (lat. 35°28'34"N., long. 108°52'21"W.)
  
  Within a 4.1-mile radius of Gallup Municipal Airport and within 1.3 miles each side of the 242° radial of the Gallup VORTAC extending from the 4.1-mile radius to 4.9 miles southwest of the airport."


Note that no limitation is given as to the time of day that the E2 airspace is in effect, and therefore it is in effect 24/7.  No specific altitude limit is stated in this section, though on page E-1 we read--


  
  General.
  
  
  Generally, if the airspace is not Class A, Class B, Class C, or Class D, and it is controlled airspace, it is Class E airspace. Class E airspace extends upward from either the surface or a designated altitude to the overlying or adjacent controlled airspace. When designated as a surface area, the airspace will be configured to contain all instrument procedures. Also in this class are Federal airways, airspace beginning at either 700 or 1,200 feet above ground level used to transition to/from the terminal or enroute environment, and enroute domestic and offshore airspace areas designated below 18,000 feet MSL. Class E airspace does not include the airspace 18,000 feet MSL or above.
You can not fly an ultralight there without prior authorization if I am reading 103.17 correctly. The way that I am reading this, it seems that you may not be in controlled airspace around an airport without prior authorization, period. And, above  18000 is a no-go as well. 

The highest concentration of aircraft traffic is at airports, Navaids like VORs, and on airways. You want to steer clear of those unless you are in clear and direct communication with those in charge of the airspace. Gallup has all three.

As far as Class E airspace, the way that 103.17 reads, It makes it sound like you are not allowed to fly in any Class E airspace over an airport without prior authorization. Admittedly, it’s splitting hairs. Everywhere else in 14 CFR, the description of Surface Class E has slightly different verbiage. 


  103.17 Operations in certain airspace.
  No person may operate an ultralight vehicle within Class A, Class B, Class C, or Class D airspace or within the lateral boundaries of the surface area of Class E airspace designated for an airport unless that person has prior authorization from the ATC facility having jurisdiction over that airspace.  
  
  137.43 Operations in controlled airspace designated for an airport.
  (b) No person may operate an aircraft in weather conditions below VFR minimums within the lateral boundaries of a Class E airspace area that extends upward from the surface unless authorization for that operation has been obtained from the ATC facility having jurisdiction over that area.  
  
  3–2–6 Class E Airspace
  1. Surface area designated for an airport where a control tower is not in operation. Class E surface areas extend upward from the surface to a designated altitude, or to the adjacent or overlying controlled airspace. The airspace will be configured to contain all instrument procedures.