I am planning to move / retire in Tarija at about the same time. as you.
I am a US citizen and my bank tells me that they will not charge me for wire transfers so my plan is to use the internet to transfer funds to that account as needed then wire transfer to a Bolivian bank.
I have not communicated with any financial institutions in Bolivia to gather what fees they may add on.
I know that currently the USD is in short supply there so I do not anticipate a bank adding any significant fee barrier. I may be too optimistic on this.
You may want to contact & query folks on the Facebook site 'º£½ÇÂÒÂ×s in Bolivia : Uncensored' and 'Bolivia Fixers'
You may friend or message me on FB also Rick Vargo.
Best of luck to your endeavors.