If you rent a car you are not subject to the restrictions. You might get stopped but as soon as you show them the rental contract you are on your way. I would suggest you get the full coverage and not worry about any damage to the car at all. Do not buy supplemental coverage online as it will do you no good for meeting the requirements of the rental car company. If you are booking online do not pay for the full coverage option as it is not correct. I just rented a car from dollar to drive to the border as mine was being worked on in town and I did not want to worry about the restriction. I rented for 3 days and paid for full coverage for a midsize SUV 262.??. When I picked it up the guy told me you should know better, do not rent online, just come in off the street and you will get a better price, also the full coverage is really partial coverage and in order to get the Days Of Thunder Coverage it was 393.?? For me well worth it but be prepared for the games, also even with the full coverage they put a 500.00 hold on my card which they have never done before with complete coverage. Oh for the record the price per day for the rental was like 26.00 per day on the website. Also I was fortunate enough to be rearended on the highway back from Golfito and you are not allowed to move the car until Transito shows up (2 Hours) and the representative from the insurance company arrives. (3 Hours) Transito did have us move to the side of the road and wait for the insurance company to show up and Transito left us there alone to wait, the person that hit us was able to leave when they were done. Kind of a crock of shit but at least we had beer in the car and drank while we waited. The insurance guys first comment was why did you move the car...... I told him because Transito told me to. I then asked him hurry up as we have been sitting here for 3 phucking hours. Put Waze on your phone if you do not already have it and you will be able to navigate with no issues providing you have cell service and do not rely on Wi Fi. I have no problems driving in Costa Rica and own a Rav4. They do drive like shit but providing you have half a brain you will have no issued driving in Costa Rica. Just pay attention to the pot holes. Also the road to Jaco has toll booths so make sure you have coins or the red 1000 colones bills. The tolls are from 560 colones to 820 colones and from Downtown I think you have 6 toll booths one way. The night of our accident we did not get out of Uvita until after 9pm at night and only saw 1 group of police just before Turrucares - Atenas and as he was walking out onto the freeway I waved at him going about 20mph over the speed limit and kept going. At this point it was about 12:15am and I was not in the mood to stop. If one of them would have chased me I would have pulled over however I was not going to be polite and stop just to show him my rental car papers.
As far as your phone goes you might want to get a Sim card in CR and use it. My wife has Movistar and Kolbi. I have a Kolbi chip I put into my Iphone when I leave the US but if I am out of the country longer than 2 months I have to remember to add a few dollars to it every couple of months or it goes dormant and I lose the credit that is on it plus I have to go to a main office and give them my passport to get it reactivated. It is cheap and with 20.00 you will not use all the funds even using Waze. the Kolbi has much better coverage than Movistar we have found. I almost never lose service and the wifes Movistar is constantly out when we travel out of the San Jose / Alajuela area.
https://llamacostarica.com/ is who I use to recharge our phone numbers from my computer.