1031 Exchange process is not difficult with the right team in place. I just completed a 1031 exchange in the spring on a multifamily transaction in Somerville. Everything was as smooth as silk and the transaction closed in under 3 weeks.
The difficult part would be finding a multifamily home in Cambridge. This year the market has been extremely slim in Cambridge and especially with multifamily properties. Right now there are only 12 properties on the market and 4 of those properties are in the sales process. This has been an extremely competitive property type as developers seem to be snatching up many of these homes to condo and turn for profit.
I would be happy to review your property and offer you my opinion on it's market value. This may help you plan the next steps in the process.
My best recommendation is to meet with an aggressive Realtor that can help you find properties quickly and you may want to look on the Somerville/ Cambridge line to expand your opportunities.