Your 353LS is one of the nicer (IMHO) models I've seen especially for full timing. Lots of room etc.
Now, that being said; Will you be parking the 5'er on the property where you will be building the new home while it's being built?
How involved will you be in the planning, construction, landscaping etc. of the new home?
Do you both still work?
If the answers are yes then this is the way I see it;
1-Gone to work most of the day
2-Busy on the details of the new home (keeping tabs on the construction crew)
3-Saving $$$ on a rental.
4-If any of the above get to be too much, just hook up and head out to escape
(everythings already loaded and ready to go).
Anyway.....just my 2 cents worth of MHO.