Historic Building modeling for LEED

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Okay, have a dormitory building renovation project that includes the following:

• Is registered on the National Register of Historic Places (1880-era), so is technically exempt from energy code requirements.
• Needs to improve over ASHRAE 90.1-2013 by 20% (per UFC 1-200-02 High Performance and Sustainable Building Requirements).
• Is pursuing LEEDv4 BD+C (ASHRAE 90.1-2010)
• Has existing HVAC system of air-cooled chiller with AHU's and VAV terminal units with reheat (gas-fired boilers). System may be replaced with new.
• Renovation will include all new lighting and electrical.
• Will include new window treatments. Opaque envelope improvements are yet unknown and may be minimal.

Curious how others would approach energy modeling for this...

1. Build three models (Proposed, 90.1-10 baseline for LEED, 90.1-13 baseline for UFC) since the envelope requirements for baseline models changed in 2013?
2. Attempt to comply with LEED requirements using LEED Interpretation ID#10481 and take the envelope baseline penalty?
3. Something else?