the LTR is 5x5 years if you still meet all the requirements after your first 5 years is up, they will give you another 5 years. My concern there is it is run by the BOI, who seem to be making statements and promises that contravene the immigration act of 1979, especially on the 90 reporting aspect.
Sorry but you are incorrect, upon arrival you will be stamped in for 45 days, then you can extend that at any immigration office for a further 30 days for a cost of 1,900 baht, you can only extend your visa exempt stamp once only. So this method will give you a total of 75 days in Thailand.
10 days in Bangkok too long in my opinion, 5 days maximum, Chiang Mai for 5 days, Koh Chang for 5 days, Kanchanaburi for a few days, Hua Hin/Cha-am for 5 days, Phuket for 7 days and then you can decide where you would like to stay longer, don’t book somewhere for a month if you haven’t tried it out, you may not like it. , there is a lot to see out here, wish you luck and enjoy your holidays.