In town for business next week, need a 5-ish mile route near DuPont/Logan Circle

What time of day?  A nice route that I would recommend is to take the Rock Creek Park trail down to the Mall area and run around the monuments. 

From Dupont you can go out P st and as soon as you cross over Rock Creek Parkway you take a hard left and loop down to the trail.  That' run right down to the Lincolin Memorial and you can grab any of the Mall pathways from there and run up to the Washington Memorial.  that should get you about 5 miles (out and back).  If you are feel up to it you can add the Mall to the Capitol from the Washington Monument, that'll add about 2 miles round trip for about 7 from Dupont Cir. and back.

You will mostly be on a trail so the only traffic issues will be at street crossings and along P st.  Fairly nice run and you go by the Watergate, Kennedy Center, Lincoln Mem., Washington Mon., The Capitol, and a host of Smithsonian Museums.